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How to Connect with a Live Customer Service Agent Play Airlines

by a.ishv.u26.0＠gmail.com

Need to talk to a real person Play Airlines? Calling Play Airlines directly at 📞 1-866-284-3022. Whether you are trying to make a flight change, cancel your booking, ask about baggage, or resolve a booking issue, reaching a live agent can save you time, stress, and confusion. While automated systems are useful for simple tasks, some situations just need a human touch. In this guide, we will walk you through exactly how to reach a live person, what to prepare before calling, and alternate methods if the phone lines are busy. ☎️ First Things First: Call 1-866-284-3022 The most direct and reliable way to speak with a real Play Airlines representative is by calling 📞 1-866-284-3022. This is Frontier’s official customer service number and should be your go-to for: ✈️ Flight changes or cancellations 🧾 Refund or credit questions 🛄 Baggage issues 🔁 Name corrections 🛑 Check-in or boarding problems 💺 Seat selection and upgrades Pro Tip: When calling, try to do so during non-peak hours — early mornings or late evenings — to reduce your hold time. 🎧 How to Navigate the Automated Menu When you call 1-866-284-3022, you will first hear an automated system. To get through to a live person faster, follow these steps: Dial 1-866-284-3022 Wait for the automated greeting to begin Press “1” for English (or “2” for Spanish) Press “2” for existing reservations Press “0” to speak with an agent (you may need to press "0" more than once) 👉 If “0” does not work immediately, stay on the line. Sometimes the system transfers you to an agent after a brief wait without needing more input. If the lines are busy and you are placed on hold, do not hang up — wait times vary, but you will eventually reach someone. 🧾 What to Have Ready Before You Call To help the agent assist you faster, make sure you have the following details on hand: 📌 Your confirmation code or booking number 📌 The full name on the reservation 📌 Your flight date and destination 📌 Any relevant documents (ID, credit card, etc.) 📌 A notepad for writing down instructions or confirmation numbers If you are calling to fix a mistake or request a refund, be prepared to briefly explain the issue and possibly provide documentation via email upon request. ⏰ Best Times to Call 1-866-284-3022 Customer service lines can be busy, especially during: ⚠️ Holidays ⚠️ Severe weather or flight delays ⚠️ Early morning flight hours 🎯 For the best chance at a short wait, try calling during these times: 🕔 5:00 AM – 7:00 AM (EST) 🕘 9:00 PM – 11:00 PM (EST) 📅 Midweek (Tuesdays and Wednesdays) Avoid Mondays if possible — it is the busiest day for airlines. 🧑‍💻 Alternative Ways to Reach Play Airlines (If Phone Fails) If calling 📞 1-866-284-3022 does not work or you are stuck in a long queue, here are a few alternate ways to get help: 💬 1. Online Chat (Limited Availability) Visit www.flyfrontier.com Scroll down and look for the “Let’s Chat” option. This can connect you to a live agent or AI assistant, depending on availability. 📧 2. Email Support You can also submit a help request through their Customer Support Form online. Use this for non-urgent matters like refund requests or documentation review. 📱 3. Social Media Tweet or DM Play Airlines on platforms like Twitter/X (@FlyFrontier) or send a message via Facebook. Sometimes social media agents respond faster than the phone team during high-volume periods. 📲 4. Mobile App Download the Play Airlines App, log in, and navigate to “My Trips” or “Support” for quick options. While this will not guarantee a live agent, you might find answers to basic questions faster. ❗ Common Issues That Require a Live Agent While many tasks can be done online, certain problems are best resolved with a real person at 1-866-284-3022: 🛑 Double charges or billing issues 🔄 Complex flight changes involving multiple passengers 🛄 Lost or delayed baggage ✍️ Legal name changes (marriage, divorce, etc.) 🧑‍⚕️ Medical or accessibility needs during travel In these cases, avoid wasting time — call directly and ask for a live agent. 🚨 Beware of Fake Numbers and Scams Only use the official number: 📞 1-866-284-3022. Scammers often post fake “Frontier support” numbers online, asking for credit card info or login credentials. 🛡️ Never share your full credit card number or personal information with an unverified source. ✅ Final Thoughts Talking to a live person at an airline should not be this hard — but when it comes to Play Airlines, knowing the right steps and phone number makes all the difference. 🧠 Remember: Dial 📞 1-866-284-3022 Press 0 to reach a live agent Call during off-peak hours Have your booking info ready Use alternative methods if the line is too busy 💡 The sooner you reach out, the more options you'll have to resolve your issue. ✈️ Whether you are rebooking, fixing an error, or checking a flight, calling 1-866-284-3022 connects you with someone who can truly help.

3 weeks, 3 days

1
0
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Connecting with a Philippine Airlines Live Agent: A Step-by-Step Guide

by a.ishv.u26.0＠gmail.com

Need to talk to a real person Philippine Airlines? Calling Philippine Airlines directly at 📞 1-866-284-3022. Whether you are trying to make a flight change, cancel your booking, ask about baggage, or resolve a booking issue, reaching a live agent can save you time, stress, and confusion. While automated systems are useful for simple tasks, some situations just need a human touch. In this guide, we will walk you through exactly how to reach a live person, what to prepare before calling, and alternate methods if the phone lines are busy. ☎️ First Things First: Call 1-866-284-3022 The most direct and reliable way to speak with a real Philippine Airlines representative is by calling 📞 1-866-284-3022. This is Frontier’s official customer service number and should be your go-to for: ✈️ Flight changes or cancellations 🧾 Refund or credit questions 🛄 Baggage issues 🔁 Name corrections 🛑 Check-in or boarding problems 💺 Seat selection and upgrades Pro Tip: When calling, try to do so during non-peak hours — early mornings or late evenings — to reduce your hold time. 🎧 How to Navigate the Automated Menu When you call 1-866-284-3022, you will first hear an automated system. To get through to a live person faster, follow these steps: Dial 1-866-284-3022 Wait for the automated greeting to begin Press “1” for English (or “2” for Spanish) Press “2” for existing reservations Press “0” to speak with an agent (you may need to press "0" more than once) 👉 If “0” does not work immediately, stay on the line. Sometimes the system transfers you to an agent after a brief wait without needing more input. If the lines are busy and you are placed on hold, do not hang up — wait times vary, but you will eventually reach someone. 🧾 What to Have Ready Before You Call To help the agent assist you faster, make sure you have the following details on hand: 📌 Your confirmation code or booking number 📌 The full name on the reservation 📌 Your flight date and destination 📌 Any relevant documents (ID, credit card, etc.) 📌 A notepad for writing down instructions or confirmation numbers If you are calling to fix a mistake or request a refund, be prepared to briefly explain the issue and possibly provide documentation via email upon request. ⏰ Best Times to Call 1-866-284-3022 Customer service lines can be busy, especially during: ⚠️ Holidays ⚠️ Severe weather or flight delays ⚠️ Early morning flight hours 🎯 For the best chance at a short wait, try calling during these times: 🕔 5:00 AM – 7:00 AM (EST) 🕘 9:00 PM – 11:00 PM (EST) 📅 Midweek (Tuesdays and Wednesdays) Avoid Mondays if possible — it is the busiest day for airlines. 🧑‍💻 Alternative Ways to Reach Philippine Airlines (If Phone Fails) If calling 📞 1-866-284-3022 does not work or you are stuck in a long queue, here are a few alternate ways to get help: 💬 1. Online Chat (Limited Availability) Visit www.flyfrontier.com Scroll down and look for the “Let’s Chat” option. This can connect you to a live agent or AI assistant, depending on availability. 📧 2. Email Support You can also submit a help request through their Customer Support Form online. Use this for non-urgent matters like refund requests or documentation review. 📱 3. Social Media Tweet or DM Philippine Airlines on platforms like Twitter/X (@FlyFrontier) or send a message via Facebook. Sometimes social media agents respond faster than the phone team during high-volume periods. 📲 4. Mobile App Download the Philippine Airlines App, log in, and navigate to “My Trips” or “Support” for quick options. While this will not guarantee a live agent, you might find answers to basic questions faster. ❗ Common Issues That Require a Live Agent While many tasks can be done online, certain problems are best resolved with a real person at 1-866-284-3022: 🛑 Double charges or billing issues 🔄 Complex flight changes involving multiple passengers 🛄 Lost or delayed baggage ✍️ Legal name changes (marriage, divorce, etc.) 🧑‍⚕️ Medical or accessibility needs during travel In these cases, avoid wasting time — call directly and ask for a live agent. 🚨 Beware of Fake Numbers and Scams Only use the official number: 📞 1-866-284-3022. Scammers often post fake “Frontier support” numbers online, asking for credit card info or login credentials. 🛡️ Never share your full credit card number or personal information with an unverified source. ✅ Final Thoughts Talking to a live person at an airline should not be this hard — but when it comes to Philippine Airlines, knowing the right steps and phone number makes all the difference. 🧠 Remember: Dial 📞 1-866-284-3022 Press 0 to reach a live agent Call during off-peak hours Have your booking info ready Use alternative methods if the line is too busy 💡 The sooner you reach out, the more options you'll have to resolve your issue. ✈️ Whether you are rebooking, fixing an error, or checking a flight, calling 1-866-284-3022 connects you with someone who can truly help.

3 weeks, 3 days

1
0
0 0

How to Contact a Live Agent Pegasus Airlines for Assistance

by a.ishv.u26.0＠gmail.com

Need to talk to a real person Pegasus Airlines? Calling Pegasus Airlines directly at 📞 1-866-284-3022. Whether you are trying to make a flight change, cancel your booking, ask about baggage, or resolve a booking issue, reaching a live agent can save you time, stress, and confusion. While automated systems are useful for simple tasks, some situations just need a human touch. In this guide, we will walk you through exactly how to reach a live person, what to prepare before calling, and alternate methods if the phone lines are busy. ☎️ First Things First: Call 1-866-284-3022 The most direct and reliable way to speak with a real Pegasus Airlines representative is by calling 📞 1-866-284-3022. This is Frontier’s official customer service number and should be your go-to for: ✈️ Flight changes or cancellations 🧾 Refund or credit questions 🛄 Baggage issues 🔁 Name corrections 🛑 Check-in or boarding problems 💺 Seat selection and upgrades Pro Tip: When calling, try to do so during non-peak hours — early mornings or late evenings — to reduce your hold time. 🎧 How to Navigate the Automated Menu When you call 1-866-284-3022, you will first hear an automated system. To get through to a live person faster, follow these steps: Dial 1-866-284-3022 Wait for the automated greeting to begin Press “1” for English (or “2” for Spanish) Press “2” for existing reservations Press “0” to speak with an agent (you may need to press "0" more than once) 👉 If “0” does not work immediately, stay on the line. Sometimes the system transfers you to an agent after a brief wait without needing more input. If the lines are busy and you are placed on hold, do not hang up — wait times vary, but you will eventually reach someone. 🧾 What to Have Ready Before You Call To help the agent assist you faster, make sure you have the following details on hand: 📌 Your confirmation code or booking number 📌 The full name on the reservation 📌 Your flight date and destination 📌 Any relevant documents (ID, credit card, etc.) 📌 A notepad for writing down instructions or confirmation numbers If you are calling to fix a mistake or request a refund, be prepared to briefly explain the issue and possibly provide documentation via email upon request. ⏰ Best Times to Call 1-866-284-3022 Customer service lines can be busy, especially during: ⚠️ Holidays ⚠️ Severe weather or flight delays ⚠️ Early morning flight hours 🎯 For the best chance at a short wait, try calling during these times: 🕔 5:00 AM – 7:00 AM (EST) 🕘 9:00 PM – 11:00 PM (EST) 📅 Midweek (Tuesdays and Wednesdays) Avoid Mondays if possible — it is the busiest day for airlines. 🧑‍💻 Alternative Ways to Reach Pegasus Airlines (If Phone Fails) If calling 📞 1-866-284-3022 does not work or you are stuck in a long queue, here are a few alternate ways to get help: 💬 1. Online Chat (Limited Availability) Visit www.flyfrontier.com Scroll down and look for the “Let’s Chat” option. This can connect you to a live agent or AI assistant, depending on availability. 📧 2. Email Support You can also submit a help request through their Customer Support Form online. Use this for non-urgent matters like refund requests or documentation review. 📱 3. Social Media Tweet or DM Pegasus Airlines on platforms like Twitter/X (@FlyFrontier) or send a message via Facebook. Sometimes social media agents respond faster than the phone team during high-volume periods. 📲 4. Mobile App Download the Pegasus Airlines App, log in, and navigate to “My Trips” or “Support” for quick options. While this will not guarantee a live agent, you might find answers to basic questions faster. ❗ Common Issues That Require a Live Agent While many tasks can be done online, certain problems are best resolved with a real person at 1-866-284-3022: 🛑 Double charges or billing issues 🔄 Complex flight changes involving multiple passengers 🛄 Lost or delayed baggage ✍️ Legal name changes (marriage, divorce, etc.) 🧑‍⚕️ Medical or accessibility needs during travel In these cases, avoid wasting time — call directly and ask for a live agent. 🚨 Beware of Fake Numbers and Scams Only use the official number: 📞 1-866-284-3022. Scammers often post fake “Frontier support” numbers online, asking for credit card info or login credentials. 🛡️ Never share your full credit card number or personal information with an unverified source. ✅ Final Thoughts Talking to a live person at an airline should not be this hard — but when it comes to Pegasus Airlines, knowing the right steps and phone number makes all the difference. 🧠 Remember: Dial 📞 1-866-284-3022 Press 0 to reach a live agent Call during off-peak hours Have your booking info ready Use alternative methods if the line is too busy 💡 The sooner you reach out, the more options you'll have to resolve your issue. ✈️ Whether you are rebooking, fixing an error, or checking a flight, calling 1-866-284-3022 connects you with someone who can truly help.

3 weeks, 3 days

1
0
0 0

How to Reach a Live Agent Mokulele Airlines: A Quick Guide

by a.ishv.u26.0＠gmail.com

Need to talk to a real person Mokulele Airlines? Calling Mokulele Airlines directly at 📞 1-866-284-3022. Whether you are trying to make a flight change, cancel your booking, ask about baggage, or resolve a booking issue, reaching a live agent can save you time, stress, and confusion. While automated systems are useful for simple tasks, some situations just need a human touch. In this guide, we will walk you through exactly how to reach a live person, what to prepare before calling, and alternate methods if the phone lines are busy. ☎️ First Things First: Call 1-866-284-3022 The most direct and reliable way to speak with a real Mokulele Airlines representative is by calling 📞 1-866-284-3022. This is Frontier’s official customer service number and should be your go-to for: ✈️ Flight changes or cancellations 🧾 Refund or credit questions 🛄 Baggage issues 🔁 Name corrections 🛑 Check-in or boarding problems 💺 Seat selection and upgrades Pro Tip: When calling, try to do so during non-peak hours — early mornings or late evenings — to reduce your hold time. 🎧 How to Navigate the Automated Menu When you call 1-866-284-3022, you will first hear an automated system. To get through to a live person faster, follow these steps: Dial 1-866-284-3022 Wait for the automated greeting to begin Press “1” for English (or “2” for Spanish) Press “2” for existing reservations Press “0” to speak with an agent (you may need to press "0" more than once) 👉 If “0” does not work immediately, stay on the line. Sometimes the system transfers you to an agent after a brief wait without needing more input. If the lines are busy and you are placed on hold, do not hang up — wait times vary, but you will eventually reach someone. 🧾 What to Have Ready Before You Call To help the agent assist you faster, make sure you have the following details on hand: 📌 Your confirmation code or booking number 📌 The full name on the reservation 📌 Your flight date and destination 📌 Any relevant documents (ID, credit card, etc.) 📌 A notepad for writing down instructions or confirmation numbers If you are calling to fix a mistake or request a refund, be prepared to briefly explain the issue and possibly provide documentation via email upon request. ⏰ Best Times to Call 1-866-284-3022 Customer service lines can be busy, especially during: ⚠️ Holidays ⚠️ Severe weather or flight delays ⚠️ Early morning flight hours 🎯 For the best chance at a short wait, try calling during these times: 🕔 5:00 AM – 7:00 AM (EST) 🕘 9:00 PM – 11:00 PM (EST) 📅 Midweek (Tuesdays and Wednesdays) Avoid Mondays if possible — it is the busiest day for airlines. 🧑‍💻 Alternative Ways to Reach Mokulele Airlines (If Phone Fails) If calling 📞 1-866-284-3022 does not work or you are stuck in a long queue, here are a few alternate ways to get help: 💬 1. Online Chat (Limited Availability) Visit www.flyfrontier.com Scroll down and look for the “Let’s Chat” option. This can connect you to a live agent or AI assistant, depending on availability. 📧 2. Email Support You can also submit a help request through their Customer Support Form online. Use this for non-urgent matters like refund requests or documentation review. 📱 3. Social Media Tweet or DM Mokulele Airlines on platforms like Twitter/X (@FlyFrontier) or send a message via Facebook. Sometimes social media agents respond faster than the phone team during high-volume periods. 📲 4. Mobile App Download the Mokulele Airlines App, log in, and navigate to “My Trips” or “Support” for quick options. While this will not guarantee a live agent, you might find answers to basic questions faster. ❗ Common Issues That Require a Live Agent While many tasks can be done online, certain problems are best resolved with a real person at 1-866-284-3022: 🛑 Double charges or billing issues 🔄 Complex flight changes involving multiple passengers 🛄 Lost or delayed baggage ✍️ Legal name changes (marriage, divorce, etc.) 🧑‍⚕️ Medical or accessibility needs during travel In these cases, avoid wasting time — call directly and ask for a live agent. 🚨 Beware of Fake Numbers and Scams Only use the official number: 📞 1-866-284-3022. Scammers often post fake “Frontier support” numbers online, asking for credit card info or login credentials. 🛡️ Never share your full credit card number or personal information with an unverified source. ✅ Final Thoughts Talking to a live person at an airline should not be this hard — but when it comes to Mokulele Airlines, knowing the right steps and phone number makes all the difference. 🧠 Remember: Dial 📞 1-866-284-3022 Press 0 to reach a live agent Call during off-peak hours Have your booking info ready Use alternative methods if the line is too busy 💡 The sooner you reach out, the more options you'll have to resolve your issue. ✈️ Whether you are rebooking, fixing an error, or checking a flight, calling 1-866-284-3022 connects you with someone who can truly help.

3 weeks, 3 days

1
0
0 0

How to Reach a Live Agent Mesa Airlines: A Quick Guide

by a.ishv.u26.0＠gmail.com

Need to talk to a real person Mesa Airlines? Calling Mesa Airlines directly at 📞 1-866-284-3022. Whether you are trying to make a flight change, cancel your booking, ask about baggage, or resolve a booking issue, reaching a live agent can save you time, stress, and confusion. While automated systems are useful for simple tasks, some situations just need a human touch. In this guide, we will walk you through exactly how to reach a live person, what to prepare before calling, and alternate methods if the phone lines are busy. ☎️ First Things First: Call 1-866-284-3022 The most direct and reliable way to speak with a real Mesa Airlines representative is by calling 📞 1-866-284-3022. This is Frontier’s official customer service number and should be your go-to for: ✈️ Flight changes or cancellations 🧾 Refund or credit questions 🛄 Baggage issues 🔁 Name corrections 🛑 Check-in or boarding problems 💺 Seat selection and upgrades Pro Tip: When calling, try to do so during non-peak hours — early mornings or late evenings — to reduce your hold time. 🎧 How to Navigate the Automated Menu When you call 1-866-284-3022, you will first hear an automated system. To get through to a live person faster, follow these steps: Dial 1-866-284-3022 Wait for the automated greeting to begin Press “1” for English (or “2” for Spanish) Press “2” for existing reservations Press “0” to speak with an agent (you may need to press "0" more than once) 👉 If “0” does not work immediately, stay on the line. Sometimes the system transfers you to an agent after a brief wait without needing more input. If the lines are busy and you are placed on hold, do not hang up — wait times vary, but you will eventually reach someone. 🧾 What to Have Ready Before You Call To help the agent assist you faster, make sure you have the following details on hand: 📌 Your confirmation code or booking number 📌 The full name on the reservation 📌 Your flight date and destination 📌 Any relevant documents (ID, credit card, etc.) 📌 A notepad for writing down instructions or confirmation numbers If you are calling to fix a mistake or request a refund, be prepared to briefly explain the issue and possibly provide documentation via email upon request. ⏰ Best Times to Call 1-866-284-3022 Customer service lines can be busy, especially during: ⚠️ Holidays ⚠️ Severe weather or flight delays ⚠️ Early morning flight hours 🎯 For the best chance at a short wait, try calling during these times: 🕔 5:00 AM – 7:00 AM (EST) 🕘 9:00 PM – 11:00 PM (EST) 📅 Midweek (Tuesdays and Wednesdays) Avoid Mondays if possible — it is the busiest day for airlines. 🧑‍💻 Alternative Ways to Reach Mesa Airlines (If Phone Fails) If calling 📞 1-866-284-3022 does not work or you are stuck in a long queue, here are a few alternate ways to get help: 💬 1. Online Chat (Limited Availability) Visit www.flyfrontier.com Scroll down and look for the “Let’s Chat” option. This can connect you to a live agent or AI assistant, depending on availability. 📧 2. Email Support You can also submit a help request through their Customer Support Form online. Use this for non-urgent matters like refund requests or documentation review. 📱 3. Social Media Tweet or DM Mesa Airlines on platforms like Twitter/X (@FlyFrontier) or send a message via Facebook. Sometimes social media agents respond faster than the phone team during high-volume periods. 📲 4. Mobile App Download the Mesa Airlines App, log in, and navigate to “My Trips” or “Support” for quick options. While this will not guarantee a live agent, you might find answers to basic questions faster. ❗ Common Issues That Require a Live Agent While many tasks can be done online, certain problems are best resolved with a real person at 1-866-284-3022: 🛑 Double charges or billing issues 🔄 Complex flight changes involving multiple passengers 🛄 Lost or delayed baggage ✍️ Legal name changes (marriage, divorce, etc.) 🧑‍⚕️ Medical or accessibility needs during travel In these cases, avoid wasting time — call directly and ask for a live agent. 🚨 Beware of Fake Numbers and Scams Only use the official number: 📞 1-866-284-3022. Scammers often post fake “Frontier support” numbers online, asking for credit card info or login credentials. 🛡️ Never share your full credit card number or personal information with an unverified source. ✅ Final Thoughts Talking to a live person at an airline should not be this hard — but when it comes to Mesa Airlines, knowing the right steps and phone number makes all the difference. 🧠 Remember: Dial 📞 1-866-284-3022 Press 0 to reach a live agent Call during off-peak hours Have your booking info ready Use alternative methods if the line is too busy 💡 The sooner you reach out, the more options you'll have to resolve your issue. ✈️ Whether you are rebooking, fixing an error, or checking a flight, calling 1-866-284-3022 connects you with someone who can truly help.

3 weeks, 3 days

1
0
0 0

[PATCH] selftests/unix: Add test for ECONNRESET and EOF behaviour

by Sunday Adelodun

Add selftests verifying the EOF and ECONNRESET behaviour of UNIX domain sockets (SOCK_STREAM and SOCK_DGRAM). The tests document Linux's semantics and clarify the long-standing differences with BSD. Suggested-by: Kuniyuki Iwashima <kuniyu(a)google.com> Signed-off-by: Sunday Adelodun <adelodunolaoluwa(a)yahoo.com> --- tools/testing/selftests/net/unix/Makefile | 5 + .../selftests/net/unix/test_unix_connreset.c | 147 ++++++++++++++++++ 2 files changed, 152 insertions(+) create mode 100644 tools/testing/selftests/net/unix/Makefile create mode 100644 tools/testing/selftests/net/unix/test_unix_connreset.c diff --git a/tools/testing/selftests/net/unix/Makefile b/tools/testing/selftests/net/unix/Makefile new file mode 100644 index 000000000000..a52992ba23d9 --- /dev/null +++ b/tools/testing/selftests/net/unix/Makefile @@ -0,0 +1,5 @@ +# SPDX-License-Identifier: GPL-2.0 +TEST_GEN_PROGS := test_unix_connreset + +include ../../lib.mk + diff --git a/tools/testing/selftests/net/unix/test_unix_connreset.c b/tools/testing/selftests/net/unix/test_unix_connreset.c new file mode 100644 index 000000000000..a8720c7565cb --- /dev/null +++ b/tools/testing/selftests/net/unix/test_unix_connreset.c @@ -0,0 +1,147 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Selftest for UNIX socket close and ECONNRESET behaviour. + * + * This test verifies that: + * 1. SOCK_STREAM sockets return EOF when peer closes normally. + * 2. SOCK_STREAM sockets return ECONNRESET if peer closes with unread data. + * 3. SOCK_DGRAM sockets do not return ECONNRESET when peer closes, + * unlike BSD where this error is observed. + * + * These tests document the intended Linux behaviour, distinguishing it from BSD. + * + */ + +#define _GNU_SOURCE +#include <stdlib.h> +#include <string.h> +#include <fcntl.h> +#include <unistd.h> +#include <errno.h> +#include <sys/socket.h> +#include <sys/un.h> +#include "../../kselftest_harness.h" + +#define SOCK_PATH "/tmp/test_unix_connreset.sock" + +static void remove_socket_file(void) +{ + unlink(SOCK_PATH); +} + +/* Test 1: peer closes normally */ +TEST(stream_eof) +{ + int server, client, child; + struct sockaddr_un addr = {0}; + char buf[16] = {0}; + ssize_t n; + + server = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(server, 0); + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + ASSERT_EQ(bind(server, (struct sockaddr *)&addr, sizeof(addr)), 0); + ASSERT_EQ(listen(server, 1), 0); + + client = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(client, 0); + ASSERT_EQ(connect(client, (struct sockaddr *)&addr, sizeof(addr)), 0); + + child = accept(server, NULL, NULL); + ASSERT_GE(child, 0); + + /* Peer closes normally */ + close(child); + + n = recv(client, buf, sizeof(buf), 0); + EXPECT_EQ(n, 0); + TH_LOG("recv=%zd errno=%d (%s)", n, errno, strerror(errno)); + + close(client); + close(server); + remove_socket_file(); +} + +/* Test 2: peer closes with unread data */ +TEST(stream_reset_unread) +{ + int server, client, child; + struct sockaddr_un addr = {0}; + char buf[16] = {0}; + ssize_t n; + + server = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(server, 0); + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + ASSERT_EQ(bind(server, (struct sockaddr *)&addr, sizeof(addr)), 0); + ASSERT_EQ(listen(server, 1), 0); + + client = socket(AF_UNIX, SOCK_STREAM, 0); + ASSERT_GE(client, 0); + ASSERT_EQ(connect(client, (struct sockaddr *)&addr, sizeof(addr)), 0); + + child = accept(server, NULL, NULL); + ASSERT_GE(child, 0); + + /* Send data that will remain unread by client */ + send(client, "hello", 5, 0); + close(child); + + n = recv(client, buf, sizeof(buf), 0); + EXPECT_LT(n, 0); + EXPECT_EQ(errno, ECONNRESET); + TH_LOG("recv=%zd errno=%d (%s)", n, errno, strerror(errno)); + + close(client); + close(server); + remove_socket_file(); +} + +/* Test 3: SOCK_DGRAM peer close */ +TEST(dgram_reset) +{ + int server, client; + int flags; + struct sockaddr_un addr = {0}; + char buf[16] = {0}; + ssize_t n; + + server = socket(AF_UNIX, SOCK_DGRAM, 0); + ASSERT_GE(server, 0); + + addr.sun_family = AF_UNIX; + strcpy(addr.sun_path, SOCK_PATH); + remove_socket_file(); + + ASSERT_EQ(bind(server, (struct sockaddr *)&addr, sizeof(addr)), 0); + + client = socket(AF_UNIX, SOCK_DGRAM, 0); + ASSERT_GE(client, 0); + ASSERT_EQ(connect(client, (struct sockaddr *)&addr, sizeof(addr)), 0); + + send(client, "hello", 5, 0); + close(server); + + flags = fcntl(client, F_GETFL, 0); + fcntl(client, F_SETFL, flags | O_NONBLOCK); + + n = recv(client, buf, sizeof(buf), 0); + TH_LOG("recv=%zd errno=%d (%s)", n, errno, strerror(errno)); + /* Expect EAGAIN or EWOULDBLOCK because there is no datagram and peer is closed. */ + EXPECT_LT(n, 0); + EXPECT_TRUE(errno == EAGAIN); + + close(client); + remove_socket_file(); +} + +TEST_HARNESS_MAIN + -- 2.43.0

3 weeks, 3 days

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[PATCH net-next 2/2] selftests: bridge_mdb: Add a test for MDB flush on snooping disable

by Petr Machata

Check that non-permanent MDB entries are removed as IGMP / MLD snooping is disabled. Signed-off-by: Petr Machata <petrm(a)nvidia.com> Reviewed-by: Ido Schimmel <idosch(a)nvidia.com> --- Notes: CC: linux-kselftest(a)vger.kernel.org CC: Shuah Khan <shuah(a)kernel.org> .../selftests/net/forwarding/bridge_mdb.sh | 100 +++++++++++++++++- 1 file changed, 98 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/net/forwarding/bridge_mdb.sh b/tools/testing/selftests/net/forwarding/bridge_mdb.sh index 8c1597ebc2d3..e86d77946585 100755 --- a/tools/testing/selftests/net/forwarding/bridge_mdb.sh +++ b/tools/testing/selftests/net/forwarding/bridge_mdb.sh @@ -28,6 +28,7 @@ ALL_TESTS=" cfg_test fwd_test ctrl_test + disable_test " NUM_NETIFS=4 @@ -64,7 +65,10 @@ h2_destroy() switch_create() { - ip link add name br0 type bridge vlan_filtering 1 vlan_default_pvid 0 \ + local vlan_filtering=$1; shift + + ip link add name br0 type bridge \ + vlan_filtering "$vlan_filtering" vlan_default_pvid 0 \ mcast_snooping 1 mcast_igmp_version 3 mcast_mld_version 2 bridge vlan add vid 10 dev br0 self bridge vlan add vid 20 dev br0 self @@ -118,7 +122,7 @@ setup_prepare() h1_create h2_create - switch_create + switch_create 1 } cleanup() @@ -1357,6 +1361,98 @@ ctrl_test() ctrl_mldv2_is_in_test } +check_group() +{ + local group=$1; shift + local vid=$1; shift + local should_fail=$1; shift + local when=$1; shift + local -a vidkws + + if ((vid)); then + vidkws=(vid "$vid") + fi + + bridge mdb get dev br0 grp "$group" "${vidkws[@]}" 2>/dev/null | + grep -q "port $swp1" + check_err_fail "$should_fail" $? "$group seen $when snooping disable:" +} + +__disable_test() +{ + local vid=$1; shift + local what=$1; shift + local -a vidkws + + if ((vid)); then + vidkws=(vid "$vid") + fi + + RET=0 + + bridge mdb add dev br0 port "$swp1" grp ff0e::1 permanent \ + "${vidkws[@]}" filter_mode include source_list 2001:db8:1::1 + bridge mdb add dev br0 port "$swp1" grp ff0e::2 permanent \ + "${vidkws[@]}" filter_mode exclude + + bridge mdb add dev br0 port "$swp1" grp ff0e::3 \ + "${vidkws[@]}" filter_mode include source_list 2001:db8:1::2 + bridge mdb add dev br0 port "$swp1" grp ff0e::4 \ + "${vidkws[@]}" filter_mode exclude + + bridge mdb add dev br0 port "$swp1" grp 239.1.1.1 permanent \ + "${vidkws[@]}" filter_mode include source_list 192.0.2.1 + bridge mdb add dev br0 port "$swp1" grp 239.1.1.2 permanent \ + "${vidkws[@]}" filter_mode exclude + + bridge mdb add dev br0 port "$swp1" grp 239.1.1.3 \ + "${vidkws[@]}" filter_mode include source_list 192.0.2.2 + bridge mdb add dev br0 port "$swp1" grp 239.1.1.4 \ + "${vidkws[@]}" filter_mode exclude + + check_group ff0e::1 "$vid" 0 "before" + check_group ff0e::2 "$vid" 0 "before" + check_group ff0e::3 "$vid" 0 "before" + check_group ff0e::4 "$vid" 0 "before" + + check_group 239.1.1.1 "$vid" 0 "before" + check_group 239.1.1.2 "$vid" 0 "before" + check_group 239.1.1.3 "$vid" 0 "before" + check_group 239.1.1.4 "$vid" 0 "before" + + ip link set dev br0 type bridge mcast_snooping 0 + + check_group ff0e::1 "$vid" 0 "after" + check_group ff0e::2 "$vid" 0 "after" + check_group ff0e::3 "$vid" 1 "after" + check_group ff0e::4 "$vid" 1 "after" + + check_group 239.1.1.1 "$vid" 0 "after" + check_group 239.1.1.2 "$vid" 0 "after" + check_group 239.1.1.3 "$vid" 1 "after" + check_group 239.1.1.4 "$vid" 1 "after" + + log_test "$what: Flush after disable" + + ip link set dev br0 type bridge mcast_snooping 1 + sleep 10 +} + +disable_test() +{ + __disable_test 10 802.1q + + switch_destroy + switch_create 0 + setup_wait + + __disable_test 0 802.1d + + switch_destroy + switch_create 1 + setup_wait +} + if ! bridge mdb help 2>&1 | grep -q "flush"; then echo "SKIP: iproute2 too old, missing bridge mdb flush support" exit $ksft_skip -- 2.49.0

3 weeks, 3 days

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[PATCH v1] selftests: cachestat: Fix warning on declaration under label

by Sidharth Seela

Fix warning caused from declaration under a case label. The proper way is to declare variable at the beginning of the function. The warning came from running clang using LLVM=1; and is as follows: -- -test_cachestat.c:260:3: warning: label followed by a declaration is a C23 extension [-Wc23-extensions] 260 | char *map = mmap(NULL, filesize, PROT_READ | PROT_WRITE, | Signed-off-by: Sidharth Seela <sidharthseela(a)gmail.com> --- diff --git a/tools/testing/selftests/cachestat/test_cachestat.c b/tools/testing/selftests/cachestat/test_cachestat.c index c952640f163b..0305e736f2b8 100644 --- a/tools/testing/selftests/cachestat/test_cachestat.c +++ b/tools/testing/selftests/cachestat/test_cachestat.c @@ -226,7 +226,7 @@ bool run_cachestat_test(enum file_type type) int syscall_ret; size_t compute_len = PS * 512; struct cachestat_range cs_range = { PS, compute_len }; - char *filename = "tmpshmcstat"; + char *filename = "tmpshmcstat", *map; struct cachestat cs; bool ret = true; int fd; @@ -257,7 +257,7 @@ bool run_cachestat_test(enum file_type type) } break; case FILE_MMAP: - char *map = mmap(NULL, filesize, PROT_READ | PROT_WRITE, + map = mmap(NULL, filesize, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); if (map == MAP_FAILED) { -- 2.47.3

3 weeks, 3 days

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[PATCH 0/3] compiler_types: Introduce __counted_by_ptr()

by Kees Cook

Hi, Add the __counted_by_ptr() macro for annotating pointer struct members with the "counted_by" attribute. Add LKDTM test, and a first user. -Kees Kees Cook (3): compiler_types: Introduce __counted_by_ptr() lkdtm/bugs: Add __counted_by_ptr() test PTR_BOUNDS coredump: Use __counted_by_ptr for struct core_name::corename init/Kconfig | 11 +++ Makefile | 4 ++ include/linux/compiler_types.h | 21 +++++- include/uapi/linux/stddef.h | 4 ++ drivers/misc/lkdtm/bugs.c | 90 ++++++++++++++++++++++--- fs/coredump.c | 8 +-- tools/testing/selftests/lkdtm/tests.txt | 2 + 7 files changed, 127 insertions(+), 13 deletions(-) -- 2.34.1

3 weeks, 3 days

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[PATCH v22 00/28] riscv control-flow integrity for usermode

by Deepak Gupta

v22: fixing build error due to -march=zicfiss being picked in gcc-13 and above but not actually doing any codegen or recognizing instruction for zicfiss. Change in v22 makes dependence on `-fcf-protection=full` compiler flag to ensure that toolchain has support and then only CONFIG_RISCV_USER_CFI will be visible in menuconfig. v21: fixed build errors. Basics and overview =================== Software with larger attack surfaces (e.g. network facing apps like databases, browsers or apps relying on browser runtimes) suffer from memory corruption issues which can be utilized by attackers to bend control flow of the program to eventually gain control (by making their payload executable). Attackers are able to perform such attacks by leveraging call-sites which rely on indirect calls or return sites which rely on obtaining return address from stack memory. To mitigate such attacks, risc-v extension zicfilp enforces that all indirect calls must land on a landing pad instruction `lpad` else cpu will raise software check exception (a new cpu exception cause code on riscv). Similarly for return flow, risc-v extension zicfiss extends architecture with - `sspush` instruction to push return address on a shadow stack - `sspopchk` instruction to pop return address from shadow stack and compare with input operand (i.e. return address on stack) - `sspopchk` to raise software check exception if comparision above was a mismatch - Protection mechanism using which shadow stack is not writeable via regular store instructions More information an details can be found at extensions github repo [1]. Equivalent to landing pad (zicfilp) on x86 is `ENDBRANCH` instruction in Intel CET [3] and branch target identification (BTI) [4] on arm. Similarly x86's Intel CET has shadow stack [5] and arm64 has guarded control stack (GCS) [6] which are very similar to risc-v's zicfiss shadow stack. x86 and arm64 support for user mode shadow stack is already in mainline. Kernel awareness for user control flow integrity ================================================ This series picks up Samuel Holland's envcfg changes [2] as well. So if those are being applied independently, they should be removed from this series. Enabling: In order to maintain compatibility and not break anything in user mode, kernel doesn't enable control flow integrity cpu extensions on binary by default. Instead exposes a prctl interface to enable, disable and lock the shadow stack or landing pad feature for a task. This allows userspace (loader) to enumerate if all objects in its address space are compiled with shadow stack and landing pad support and accordingly enable the feature. Additionally if a subsequent `dlopen` happens on a library, user mode can take a decision again to disable the feature (if incoming library is not compiled with support) OR terminate the task (if user mode policy is strict to have all objects in address space to be compiled with control flow integirty cpu feature). prctl to enable shadow stack results in allocating shadow stack from virtual memory and activating for user address space. x86 and arm64 are also following same direction due to similar reason(s). clone/fork: On clone and fork, cfi state for task is inherited by child. Shadow stack is part of virtual memory and is a writeable memory from kernel perspective (writeable via a restricted set of instructions aka shadow stack instructions) Thus kernel changes ensure that this memory is converted into read-only when fork/clone happens and COWed when fault is taken due to sspush, sspopchk or ssamoswap. In case `CLONE_VM` is specified and shadow stack is to be enabled, kernel will automatically allocate a shadow stack for that clone call. map_shadow_stack: x86 introduced `map_shadow_stack` system call to allow user space to explicitly map shadow stack memory in its address space. It is useful to allocate shadow for different contexts managed by a single thread (green threads or contexts) risc-v implements this system call as well. signal management: If shadow stack is enabled for a task, kernel performs an asynchronous control flow diversion to deliver the signal and eventually expects userspace to issue sigreturn so that original execution can be resumed. Even though resume context is prepared by kernel, it is in user space memory and is subject to memory corruption and corruption bugs can be utilized by attacker in this race window to perform arbitrary sigreturn and eventually bypass cfi mechanism. Another issue is how to ensure that cfi related state on sigcontext area is not trampled by legacy apps or apps compiled with old kernel headers. In order to mitigate control-flow hijacting, kernel prepares a token and place it on shadow stack before signal delivery and places address of token in sigcontext structure. During sigreturn, kernel obtains address of token from sigcontext struture, reads token from shadow stack and validates it and only then allow sigreturn to succeed. Compatiblity issue is solved by adopting dynamic sigcontext management introduced for vector extension. This series re-factor the code little bit to allow future sigcontext management easy (as proposed by Andy Chiu from SiFive) config and compilation: Introduce a new risc-v config option `CONFIG_RISCV_USER_CFI`. Selecting this config option picks the kernel support for user control flow integrity. This optin is presented only if toolchain has shadow stack and landing pad support. And is on purpose guarded by toolchain support. Reason being that eventually vDSO also needs to be compiled in with shadow stack and landing pad support. vDSO compile patches are not included as of now because landing pad labeling scheme is yet to settle for usermode runtime. To get more information on kernel interactions with respect to zicfilp and zicfiss, patch series adds documentation for `zicfilp` and `zicfiss` in following: Documentation/arch/riscv/zicfiss.rst Documentation/arch/riscv/zicfilp.rst How to test this series ======================= Toolchain --------- $ git clone git@github.com:sifive/riscv-gnu-toolchain.git -b cfi-dev $ riscv-gnu-toolchain/configure --prefix=<path-to-where-to-build> --with-arch=rv64gc_zicfilp_zicfiss --enable-linux --disable-gdb --with-extra-multilib-test="rv64gc_zicfilp_zicfiss-lp64d:-static" $ make -j$(nproc) Qemu ---- Get the lastest qemu $ cd qemu $ mkdir build $ cd build $ ../configure --target-list=riscv64-softmmu $ make -j$(nproc) Opensbi ------- $ git clone git@github.com:deepak0414/opensbi.git -b v6_cfi_spec_split_opensbi $ make CROSS_COMPILE=<your riscv toolchain> -j$(nproc) PLATFORM=generic Linux ----- Running defconfig is fine. CFI is enabled by default if the toolchain supports it. $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) defconfig $ make ARCH=riscv CROSS_COMPILE=<path-to-cfi-riscv-gnu-toolchain>/build/bin/riscv64-unknown-linux-gnu- -j$(nproc) Running ------- Modify your qemu command to have: -bios <path-to-cfi-opensbi>/build/platform/generic/firmware/fw_dynamic.bin -cpu rv64,zicfilp=true,zicfiss=true,zimop=true,zcmop=true References ========== [1] - https://github.com/riscv/riscv-cfi [2] - https://lore.kernel.org/all/20240814081126.956287-1-samuel.holland@sifive.c… [3] - https://lwn.net/Articles/889475/ [4] - https://developer.arm.com/documentation/109576/0100/Branch-Target-Identific… [5] - https://www.intel.com/content/dam/develop/external/us/en/documents/catc17-i… [6] - https://lwn.net/Articles/940403/ To: Thomas Gleixner <tglx(a)linutronix.de> To: Ingo Molnar <mingo(a)redhat.com> To: Borislav Petkov <bp(a)alien8.de> To: Dave Hansen <dave.hansen(a)linux.intel.com> To: x86(a)kernel.org To: H. Peter Anvin <hpa(a)zytor.com> To: Andrew Morton <akpm(a)linux-foundation.org> To: Liam R. Howlett <Liam.Howlett(a)oracle.com> To: Vlastimil Babka <vbabka(a)suse.cz> To: Lorenzo Stoakes <lorenzo.stoakes(a)oracle.com> To: Paul Walmsley <paul.walmsley(a)sifive.com> To: Palmer Dabbelt <palmer(a)dabbelt.com> To: Albert Ou <aou(a)eecs.berkeley.edu> To: Conor Dooley <conor(a)kernel.org> To: Rob Herring <robh(a)kernel.org> To: Krzysztof Kozlowski <krzk+dt(a)kernel.org> To: Arnd Bergmann <arnd(a)arndb.de> To: Christian Brauner <brauner(a)kernel.org> To: Peter Zijlstra <peterz(a)infradead.org> To: Oleg Nesterov <oleg(a)redhat.com> To: Eric Biederman <ebiederm(a)xmission.com> To: Kees Cook <kees(a)kernel.org> To: Jonathan Corbet <corbet(a)lwn.net> To: Shuah Khan <shuah(a)kernel.org> To: Jann Horn <jannh(a)google.com> To: Conor Dooley <conor+dt(a)kernel.org> To: Miguel Ojeda <ojeda(a)kernel.org> To: Alex Gaynor <alex.gaynor(a)gmail.com> To: Boqun Feng <boqun.feng(a)gmail.com> To: Gary Guo <gary(a)garyguo.net> To: Björn Roy Baron <bjorn3_gh(a)protonmail.com> To: Benno Lossin <benno.lossin(a)proton.me> To: Andreas Hindborg <a.hindborg(a)kernel.org> To: Alice Ryhl <aliceryhl(a)google.com> To: Trevor Gross <tmgross(a)umich.edu> Cc: linux-kernel(a)vger.kernel.org Cc: linux-fsdevel(a)vger.kernel.org Cc: linux-mm(a)kvack.org Cc: linux-riscv(a)lists.infradead.org Cc: devicetree(a)vger.kernel.org Cc: linux-arch(a)vger.kernel.org Cc: linux-doc(a)vger.kernel.org Cc: linux-kselftest(a)vger.kernel.org Cc: alistair.francis(a)wdc.com Cc: richard.henderson(a)linaro.org Cc: jim.shu(a)sifive.com Cc: andybnac(a)gmail.com Cc: kito.cheng(a)sifive.com Cc: charlie(a)rivosinc.com Cc: atishp(a)rivosinc.com Cc: evan(a)rivosinc.com Cc: cleger(a)rivosinc.com Cc: alexghiti(a)rivosinc.com Cc: samitolvanen(a)google.com Cc: broonie(a)kernel.org Cc: rick.p.edgecombe(a)intel.com Cc: rust-for-linux(a)vger.kernel.org changelog --------- v22: - CONFIG_RISCV_USER_CFI was by default "n". With dual vdso support it is default "y" (if toolchain supports it). Fixing build error due to "-march=zicfiss" being picked in gcc-13 partially. gcc-13 only recognizes the flag but not actually doing any codegen or recognizing instruction for zicfiss. Change in v22 makes dependence on `-fcf-protection=full` compiler flag to ensure that toolchain has support and then only CONFIG_RISCV_USER_CFI will be visible in menuconfig. - picked up tags and some cosmetic changes in commit message for dual vdso patch. v21: - Fixing build errors due to changes in arch/riscv/include/asm/vdso.h Using #ifdef instead of IS_ENABLED in arch/riscv/include/asm/vdso.h vdso-cfi-offsets.h should be included only when CONFIG_RISCV_USER_CFI is selected. v20: - rebased on v6.18-rc1. - Added two vDSO support. If `CONFIG_RISCV_USER_CFI` is selected two vDSOs are compiled (one for hardware prior to RVA23 and one for RVA23 onwards). Kernel exposes RVA23 vDSO if hardware/cpu implements zimop else exposes existing vDSO to userspace. - default selection for `CONFIG_RISCV_USER_CFI` is "Yes". - replaced "__ASSEMBLY__" with "__ASSEMBLER__" v19: - riscv_nousercfi was `int`. changed it to unsigned long. Thanks to Alex Ghiti for reporting it. It was a bug. - ELP is cleared on trap entry only when CONFIG_64BIT. - restore ssp back on return to usermode was being done before `riscv_v_context_nesting_end` on trap exit path. If kernel shadow stack were enabled this would result in kernel operating on user shadow stack and panic (as I found in my testing of kcfi patch series). So fixed that. v18: - rebased on 6.16-rc1 - uprobe handling clears ELP in sstatus image in pt_regs - vdso was missing shadow stack elf note for object files. added that. Additional asm file for vdso needed the elf marker flag. toolchain should complain if `-fcf-protection=full` and marker is missing for object generated from asm file. Asked toolchain folks to fix this. Although no reason to gate the merge on that. - Split up compile options for march and fcf-protection in vdso Makefile - CONFIG_RISCV_USER_CFI option is moved under "Kernel features" menu Added `arch/riscv/configs/hardening.config` fragment which selects CONFIG_RISCV_USER_CFI v17: - fixed warnings due to empty macros in usercfi.h (reported by alexg) - fixed prefixes in commit titles reported by alexg - took below uprobe with fcfi v2 patch from Zong Li and squashed it with "riscv/traps: Introduce software check exception and uprobe handling" https://lore.kernel.org/all/20250604093403.10916-1-zong.li@sifive.com/ v16: - If FWFT is not implemented or returns error for shadow stack activation, then no_usercfi is set to disable shadow stack. Although this should be picked up by extension validation and activation. Fixed this bug for zicfilp and zicfiss both. Thanks to Charlie Jenkins for reporting this. - If toolchain doesn't support cfi, cfi kselftest shouldn't build. Suggested by Charlie Jenkins. - Default for CONFIG_RISCV_USER_CFI is set to no. Charlie/Atish suggested to keep it off till we have more hardware availibility with RVA23 profile and zimop/zcmop implemented. Else this will start breaking people's workflow - Includes the fix if "!RV64 and !SBI" then definitions for FWFT in asm-offsets.c error. v15: - Toolchain has been updated to include `-fcf-protection` flag. This exists for x86 as well. Updated kernel patches to compile vDSO and selftest to compile with `fcf-protection=full` flag. - selecting CONFIG_RISCV_USERCFI selects CONFIG_RISCV_SBI. - Patch to enable shadow stack for kernel wasn't hidden behind CONFIG_RISCV_USERCFI and CONFIG_RISCV_SBI. fixed that. v14: - rebased on top of palmer/sbi-v3. Thus dropped clement's FWFT patches Updated RISCV_ISA_EXT_XXXX in hwcap and hwprobe constants. - Took Radim's suggestions on bitfields. - Placed cfi_state at the end of thread_info block so that current situation is not disturbed with respect to member fields of thread_info in single cacheline. v13: - cpu_supports_shadow_stack/cpu_supports_indirect_br_lp_instr uses riscv_has_extension_unlikely() - uses nops(count) to create nop slide - RISCV_ACQUIRE_BARRIER is not needed in `amo_user_shstk`. Removed it - changed ternaries to simply use implicit casting to convert to bool. - kernel command line allows to disable zicfilp and zicfiss independently. updated kernel-parameters.txt. - ptrace user abi for cfi uses bitmasks instead of bitfields. Added ptrace kselftest. - cosmetic and grammatical changes to documentation. v12: - It seems like I had accidently squashed arch agnostic indirect branch tracking prctl and riscv implementation of those prctls. Split them again. - set_shstk_status/set_indir_lp_status perform CSR writes only when CPU support is available. As suggested by Zong Li. - Some minor clean up in kselftests as suggested by Zong Li. v11: - patch "arch/riscv: compile vdso with landing pad" was unconditionally selecting `_zicfilp` for vDSO compile. fixed that. Changed `lpad 1` to to `lpad 0`. v10: - dropped "mm: helper `is_shadow_stack_vma` to check shadow stack vma". This patch is not that interesting to this patch series for risc-v. There are instances in arch directories where VM_SHADOW_STACK flag is anyways used. Dropping this patch to expedite merging in riscv tree. - Took suggestions from `Clement` on "riscv: zicfiss / zicfilp enumeration" to validate presence of cfi based on config. - Added a patch for vDSO to have `lpad 0`. I had omitted this earlier to make sure we add single vdso object with cfi enabled. But a vdso object with scheme of zero labeled landing pad is least common denominator and should work with all objects of zero labeled as well as function-signature labeled objects. v9: - rebased on master (39a803b754d5 fix braino in "9p: fix ->rename_sem exclusion") - dropped "mm: Introduce ARCH_HAS_USER_SHADOW_STACK" (master has it from arm64/gcs) - dropped "prctl: arch-agnostic prctl for shadow stack" (master has it from arm64/gcs) v8: - rebased on palmer/for-next - dropped samuel holland's `envcfg` context switch patches. they are in parlmer/for-next v7: - Removed "riscv/Kconfig: enable HAVE_EXIT_THREAD for riscv" Instead using `deactivate_mm` flow to clean up. see here for more context https://lore.kernel.org/all/20230908203655.543765-1-rick.p.edgecombe@intel.… - Changed the header include in `kselftest`. Hopefully this fixes compile issue faced by Zong Li at SiFive. - Cleaned up an orphaned change to `mm/mmap.c` in below patch "riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE" - Lock interfaces for shadow stack and indirect branch tracking expect arg == 0 Any future evolution of this interface should accordingly define how arg should be setup. - `mm/map.c` has an instance of using `VM_SHADOW_STACK`. Fixed it to use helper `is_shadow_stack_vma`. - Link to v6: https://lore.kernel.org/r/20241008-v5_user_cfi_series-v6-0-60d9fe073f37@riv… v6: - Picked up Samuel Holland's changes as is with `envcfg` placed in `thread` instead of `thread_info` - fixed unaligned newline escapes in kselftest - cleaned up messages in kselftest and included test output in commit message - fixed a bug in clone path reported by Zong Li - fixed a build issue if CONFIG_RISCV_ISA_V is not selected (this was introduced due to re-factoring signal context management code) v5: - rebased on v6.12-rc1 - Fixed schema related issues in device tree file - Fixed some of the documentation related issues in zicfilp/ss.rst (style issues and added index) - added `SHADOW_STACK_SET_MARKER` so that implementation can define base of shadow stack. - Fixed warnings on definitions added in usercfi.h when CONFIG_RISCV_USER_CFI is not selected. - Adopted context header based signal handling as proposed by Andy Chiu - Added support for enabling kernel mode access to shadow stack using FWFT (https://github.com/riscv-non-isa/riscv-sbi-doc/blob/master/src/ext-firmware…) - Link to v5: https://lore.kernel.org/r/20241001-v5_user_cfi_series-v1-0-3ba65b6e550f@riv… (Note: I had an issue in my workflow due to which version number wasn't picked up correctly while sending out patches) v4: - rebased on 6.11-rc6 - envcfg: Converged with Samuel Holland's patches for envcfg management on per- thread basis. - vma_is_shadow_stack is renamed to is_vma_shadow_stack - picked up Mark Brown's `ARCH_HAS_USER_SHADOW_STACK` patch - signal context: using extended context management to maintain compatibility. - fixed `-Wmissing-prototypes` compiler warnings for prctl functions - Documentation fixes and amending typos. - Link to v4: https://lore.kernel.org/all/20240912231650.3740732-1-debug@rivosinc.com/ v3: - envcfg logic to pick up base envcfg had a bug where `ENVCFG_CBZE` could have been picked on per task basis, even though CPU didn't implement it. Fixed in this series. - dt-bindings As suggested, split into separate commit. fixed the messaging that spec is in public review - arch_is_shadow_stack change arch_is_shadow_stack changed to vma_is_shadow_stack - hwprobe zicfiss / zicfilp if present will get enumerated in hwprobe - selftests As suggested, added object and binary filenames to .gitignore Selftest binary anyways need to be compiled with cfi enabled compiler which will make sure that landing pad and shadow stack are enabled. Thus removed separate enable/disable tests. Cleaned up tests a bit. - Link to v3: https://lore.kernel.org/lkml/20240403234054.2020347-1-debug@rivosinc.com/ v2: - Using config `CONFIG_RISCV_USER_CFI`, kernel support for riscv control flow integrity for user mode programs can be compiled in the kernel. - Enabling of control flow integrity for user programs is left to user runtime - This patch series introduces arch agnostic `prctls` to enable shadow stack and indirect branch tracking. And implements them on riscv. --- Changes in v22: - Link to v21: https://lore.kernel.org/r/20251015-v5_user_cfi_series-v21-0-6a07856e90e7@ri… Changes in v21: - Link to v20: https://lore.kernel.org/r/20251013-v5_user_cfi_series-v20-0-b9de4be9912e@ri… Changes in v20: - Link to v19: https://lore.kernel.org/r/20250731-v5_user_cfi_series-v19-0-09b468d7beab@ri… Changes in v19: - Link to v18: https://lore.kernel.org/r/20250711-v5_user_cfi_series-v18-0-a8ee62f9f38e@ri… Changes in v18: - Link to v17: https://lore.kernel.org/r/20250604-v5_user_cfi_series-v17-0-4565c2cf869f@ri… Changes in v17: - Link to v16: https://lore.kernel.org/r/20250522-v5_user_cfi_series-v16-0-64f61a35eee7@ri… Changes in v16: - Link to v15: https://lore.kernel.org/r/20250502-v5_user_cfi_series-v15-0-914966471885@ri… Changes in v15: - changelog posted just below cover letter - Link to v14: https://lore.kernel.org/r/20250429-v5_user_cfi_series-v14-0-5239410d012a@ri… Changes in v14: - changelog posted just below cover letter - Link to v13: https://lore.kernel.org/r/20250424-v5_user_cfi_series-v13-0-971437de586a@ri… Changes in v13: - changelog posted just below cover letter - Link to v12: https://lore.kernel.org/r/20250314-v5_user_cfi_series-v12-0-e51202b53138@ri… Changes in v12: - changelog posted just below cover letter - Link to v11: https://lore.kernel.org/r/20250310-v5_user_cfi_series-v11-0-86b36cbfb910@ri… Changes in v11: - changelog posted just below cover letter - Link to v10: https://lore.kernel.org/r/20250210-v5_user_cfi_series-v10-0-163dcfa31c60@ri… --- Andy Chiu (1): riscv: signal: abstract header saving for setup_sigcontext Deepak Gupta (26): mm: VM_SHADOW_STACK definition for riscv dt-bindings: riscv: zicfilp and zicfiss in dt-bindings (extensions.yaml) riscv: zicfiss / zicfilp enumeration riscv: zicfiss / zicfilp extension csr and bit definitions riscv: usercfi state for task and save/restore of CSR_SSP on trap entry/exit riscv/mm : ensure PROT_WRITE leads to VM_READ | VM_WRITE riscv/mm: manufacture shadow stack pte riscv/mm: teach pte_mkwrite to manufacture shadow stack PTEs riscv/mm: write protect and shadow stack riscv/mm: Implement map_shadow_stack() syscall riscv/shstk: If needed allocate a new shadow stack on clone riscv: Implements arch agnostic shadow stack prctls prctl: arch-agnostic prctl for indirect branch tracking riscv: Implements arch agnostic indirect branch tracking prctls riscv/traps: Introduce software check exception and uprobe handling riscv/signal: save and restore of shadow stack for signal riscv/kernel: update __show_regs to print shadow stack register riscv/ptrace: riscv cfi status and state via ptrace and in core files riscv/hwprobe: zicfilp / zicfiss enumeration in hwprobe riscv: kernel command line option to opt out of user cfi riscv: enable kernel access to shadow stack memory via FWFT sbi call arch/riscv: dual vdso creation logic and select vdso based on hw riscv: create a config for shadow stack and landing pad instr support riscv: Documentation for landing pad / indirect branch tracking riscv: Documentation for shadow stack on riscv kselftest/riscv: kselftest for user mode cfi Jim Shu (1): arch/riscv: compile vdso with landing pad and shadow stack note Documentation/admin-guide/kernel-parameters.txt | 8 + Documentation/arch/riscv/index.rst | 2 + Documentation/arch/riscv/zicfilp.rst | 115 +++++ Documentation/arch/riscv/zicfiss.rst | 179 +++++++ .../devicetree/bindings/riscv/extensions.yaml | 14 + arch/riscv/Kconfig | 22 + arch/riscv/Makefile | 8 +- arch/riscv/configs/hardening.config | 4 + arch/riscv/include/asm/asm-prototypes.h | 1 + arch/riscv/include/asm/assembler.h | 44 ++ arch/riscv/include/asm/cpufeature.h | 12 + arch/riscv/include/asm/csr.h | 16 + arch/riscv/include/asm/entry-common.h | 2 + arch/riscv/include/asm/hwcap.h | 2 + arch/riscv/include/asm/mman.h | 26 + arch/riscv/include/asm/mmu_context.h | 7 + arch/riscv/include/asm/pgtable.h | 30 +- arch/riscv/include/asm/processor.h | 1 + arch/riscv/include/asm/thread_info.h | 3 + arch/riscv/include/asm/usercfi.h | 95 ++++ arch/riscv/include/asm/vdso.h | 13 +- arch/riscv/include/asm/vector.h | 3 + arch/riscv/include/uapi/asm/hwprobe.h | 2 + arch/riscv/include/uapi/asm/ptrace.h | 34 ++ arch/riscv/include/uapi/asm/sigcontext.h | 1 + arch/riscv/kernel/Makefile | 2 + arch/riscv/kernel/asm-offsets.c | 10 + arch/riscv/kernel/cpufeature.c | 27 + arch/riscv/kernel/entry.S | 38 ++ arch/riscv/kernel/head.S | 27 + arch/riscv/kernel/process.c | 27 +- arch/riscv/kernel/ptrace.c | 95 ++++ arch/riscv/kernel/signal.c | 148 +++++- arch/riscv/kernel/sys_hwprobe.c | 2 + arch/riscv/kernel/sys_riscv.c | 10 + arch/riscv/kernel/traps.c | 54 ++ arch/riscv/kernel/usercfi.c | 545 +++++++++++++++++++++ arch/riscv/kernel/vdso.c | 7 + arch/riscv/kernel/vdso/Makefile | 40 +- arch/riscv/kernel/vdso/flush_icache.S | 4 + arch/riscv/kernel/vdso/gen_vdso_offsets.sh | 4 +- arch/riscv/kernel/vdso/getcpu.S | 4 + arch/riscv/kernel/vdso/note.S | 3 + arch/riscv/kernel/vdso/rt_sigreturn.S | 4 + arch/riscv/kernel/vdso/sys_hwprobe.S | 4 + arch/riscv/kernel/vdso/vgetrandom-chacha.S | 5 +- arch/riscv/kernel/vdso_cfi/Makefile | 25 + arch/riscv/kernel/vdso_cfi/vdso-cfi.S | 11 + arch/riscv/mm/init.c | 2 +- arch/riscv/mm/pgtable.c | 16 + include/linux/cpu.h | 4 + include/linux/mm.h | 7 + include/uapi/linux/elf.h | 2 + include/uapi/linux/prctl.h | 27 + kernel/sys.c | 30 ++ tools/testing/selftests/riscv/Makefile | 2 +- tools/testing/selftests/riscv/cfi/.gitignore | 3 + tools/testing/selftests/riscv/cfi/Makefile | 16 + tools/testing/selftests/riscv/cfi/cfi_rv_test.h | 82 ++++ tools/testing/selftests/riscv/cfi/riscv_cfi_test.c | 173 +++++++ tools/testing/selftests/riscv/cfi/shadowstack.c | 385 +++++++++++++++ tools/testing/selftests/riscv/cfi/shadowstack.h | 27 + 62 files changed, 2475 insertions(+), 41 deletions(-) --- base-commit: 3a8660878839faadb4f1a6dd72c3179c1df56787 change-id: 20240930-v5_user_cfi_series-3dc332f8f5b2 -- - 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