April 2025 - Linux-kselftest-mirror

[PATCH bpf v2 0/2] bpf, xdp: clean adjust_{head,meta} memory when offset < 0

by Jiayuan Chen

This patchset originates from my attempt to resolve a KMSAN warning that has existed for over 3 years: https://syzkaller.appspot.com/bug?extid=0e6ddb1ef80986bdfe64 Previously, we had a brief discussion in this thread about whether we can simply perform memset in adjust_{head,meta}: https://lore.kernel.org/netdev/20250328043941.085de23b@kernel.org/T/#t Unfortunately, I couldn't find a similar topic in the mail list, but I did find a similar security-related commit: commit 6dfb970d3dbd ("xdp: avoid leaking info stored in frame data on page reuse") I just create a new topic here and make subject more clear, we can discuss this here. Meanwhile, I also discovered a related issue that led to a CVE,specifically the Facebook Katran vulnerability (https://vuldb.com/?id.246309). Currently, even with unprivileged functionality disabled, a user can load a BPF program using CAP_BPF and CAP_NET_ADMIN, which I believe we should avoid exposing kernel memory directly to users now. Regarding performance considerations, I added corresponding results to the selftest, testing common MAC headers and IP headers of various sizes. Compared to not using memset, the execution time increased by 2ns, but I think this is negligible considering the entire net stack. Jiayuan Chen (2): bpf, xdp: clean head/meta when expanding it selftests/bpf: add perf test for adjust_{head,meta} include/uapi/linux/bpf.h | 8 +-- net/core/filter.c | 5 +- tools/include/uapi/linux/bpf.h | 6 ++- .../selftests/bpf/prog_tests/xdp_perf.c | 52 ++++++++++++++++--- tools/testing/selftests/bpf/progs/xdp_dummy.c | 14 +++++ 5 files changed, 72 insertions(+), 13 deletions(-) -- 2.47.1

3 weeks, 4 days

5
10
0 0

[PATCH AUTOSEL 6.12 01/20] selftests/bpf: Fix stdout race condition in traffic monitor

by Sasha Levin

From: Amery Hung <ameryhung(a)gmail.com> [ Upstream commit b99f27e90268b1a814c13f8bd72ea1db448ea257 ] Fix a race condition between the main test_progs thread and the traffic monitoring thread. The traffic monitor thread tries to print a line using multiple printf and use flockfile() to prevent the line from being torn apart. Meanwhile, the main thread doing io redirection can reassign or close stdout when going through tests. A deadlock as shown below can happen. main traffic_monitor_thread ==== ====================== show_transport() -> flockfile(stdout) stdio_hijack_init() -> stdout = open_memstream(log_buf, log_cnt); ... env.subtest_state->stdout_saved = stdout; ... funlockfile(stdout) stdio_restore_cleanup() -> fclose(env.subtest_state->stdout_saved); After the traffic monitor thread lock stdout, A new memstream can be assigned to stdout by the main thread. Therefore, the traffic monitor thread later will not be able to unlock the original stdout. As the main thread tries to access the old stdout, it will hang indefinitely as it is still locked by the traffic monitor thread. The deadlock can be reproduced by running test_progs repeatedly with traffic monitor enabled: for ((i=1;i<=100;i++)); do ./test_progs -a flow_dissector_skb* -m '*' done Fix this by only calling printf once and remove flockfile()/funlockfile(). Signed-off-by: Amery Hung <ameryhung(a)gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau(a)kernel.org> Link: https://patch.msgid.link/20250213233217.553258-1-ameryhung@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/network_helpers.c | 33 ++++++++----------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 27784946b01b8..af0ee70a53f9f 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -771,12 +771,13 @@ static const char *pkt_type_str(u16 pkt_type) return "Unknown"; } +#define MAX_FLAGS_STRLEN 21 /* Show the information of the transport layer in the packet */ static void show_transport(const u_char *packet, u16 len, u32 ifindex, const char *src_addr, const char *dst_addr, u16 proto, bool ipv6, u8 pkt_type) { - char *ifname, _ifname[IF_NAMESIZE]; + char *ifname, _ifname[IF_NAMESIZE], flags[MAX_FLAGS_STRLEN] = ""; const char *transport_str; u16 src_port, dst_port; struct udphdr *udp; @@ -817,29 +818,21 @@ static void show_transport(const u_char *packet, u16 len, u32 ifindex, /* TCP or UDP*/ - flockfile(stdout); + if (proto == IPPROTO_TCP) + snprintf(flags, MAX_FLAGS_STRLEN, "%s%s%s%s", + tcp->fin ? ", FIN" : "", + tcp->syn ? ", SYN" : "", + tcp->rst ? ", RST" : "", + tcp->ack ? ", ACK" : ""); + if (ipv6) - printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d", + printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); + dst_addr, dst_port, transport_str, len, flags); else - printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d", + printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); - - if (proto == IPPROTO_TCP) { - if (tcp->fin) - printf(", FIN"); - if (tcp->syn) - printf(", SYN"); - if (tcp->rst) - printf(", RST"); - if (tcp->ack) - printf(", ACK"); - } - - printf("\n"); - funlockfile(stdout); + dst_addr, dst_port, transport_str, len, flags); } static void show_ipv6_packet(const u_char *packet, u32 ifindex, u8 pkt_type) -- 2.39.5

3 weeks, 4 days

1
0
0 0

[PATCH AUTOSEL 6.13 16/22] selftests/bpf: Fix cap_enable_effective() return code

by Sasha Levin

From: Feng Yang <yangfeng(a)kylinos.cn> [ Upstream commit 339c1f8ea11cc042c30c315c1a8f61e4b8a90117 ] The caller of cap_enable_effective() expects negative error code. Fix it. Before: failed to restore CAP_SYS_ADMIN: -1, Unknown error -1 After: failed to restore CAP_SYS_ADMIN: -3, No such process failed to restore CAP_SYS_ADMIN: -22, Invalid argument Signed-off-by: Feng Yang <yangfeng(a)kylinos.cn> Acked-by: Eduard Zingerman <eddyz87(a)gmail.com> Link: https://lore.kernel.org/r/20250305022234.44932-1-yangfeng59949@163.com Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/cap_helpers.c | 8 ++++---- tools/testing/selftests/bpf/cap_helpers.h | 1 + tools/testing/selftests/bpf/prog_tests/verifier.c | 4 ++-- tools/testing/selftests/bpf/test_loader.c | 6 +++--- 4 files changed, 10 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/bpf/cap_helpers.c b/tools/testing/selftests/bpf/cap_helpers.c index d5ac507401d7c..98f840c3a38f7 100644 --- a/tools/testing/selftests/bpf/cap_helpers.c +++ b/tools/testing/selftests/bpf/cap_helpers.c @@ -19,7 +19,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -32,7 +32,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) data[1].effective |= cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } @@ -49,7 +49,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -61,7 +61,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) data[1].effective &= ~cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } diff --git a/tools/testing/selftests/bpf/cap_helpers.h b/tools/testing/selftests/bpf/cap_helpers.h index 6d163530cb0fd..8dcb28557f762 100644 --- a/tools/testing/selftests/bpf/cap_helpers.h +++ b/tools/testing/selftests/bpf/cap_helpers.h @@ -4,6 +4,7 @@ #include <linux/types.h> #include <linux/capability.h> +#include <errno.h> #ifndef CAP_PERFMON #define CAP_PERFMON 38 diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 3ee40ee9413a9..88cb75b65cecd 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -118,7 +118,7 @@ static void run_tests_aux(const char *skel_name, /* test_verifier tests are executed w/o CAP_SYS_ADMIN, do the same here */ err = cap_disable_effective(1ULL << CAP_SYS_ADMIN, &old_caps); if (err) { - PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); return; } @@ -128,7 +128,7 @@ static void run_tests_aux(const char *skel_name, err = cap_enable_effective(old_caps, NULL); if (err) - PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); } #define RUN(skel) run_tests_aux(#skel, skel##__elf_bytes, NULL) diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c index 53b06647cf57d..8a403e5aa3145 100644 --- a/tools/testing/selftests/bpf/test_loader.c +++ b/tools/testing/selftests/bpf/test_loader.c @@ -773,7 +773,7 @@ static int drop_capabilities(struct cap_state *caps) err = cap_disable_effective(caps_to_drop, &caps->old_caps); if (err) { - PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(-err)); return err; } @@ -790,7 +790,7 @@ static int restore_capabilities(struct cap_state *caps) err = cap_enable_effective(caps->old_caps, NULL); if (err) - PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(-err)); caps->initialized = false; return err; } @@ -959,7 +959,7 @@ void run_subtest(struct test_loader *tester, if (subspec->caps) { err = cap_enable_effective(subspec->caps, NULL); if (err) { - PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(-err)); goto subtest_cleanup; } } -- 2.39.5

3 weeks, 4 days

1
0
0 0

[PATCH AUTOSEL 6.13 02/22] selftests/bpf: Fix stdout race condition in traffic monitor

by Sasha Levin

From: Amery Hung <ameryhung(a)gmail.com> [ Upstream commit b99f27e90268b1a814c13f8bd72ea1db448ea257 ] Fix a race condition between the main test_progs thread and the traffic monitoring thread. The traffic monitor thread tries to print a line using multiple printf and use flockfile() to prevent the line from being torn apart. Meanwhile, the main thread doing io redirection can reassign or close stdout when going through tests. A deadlock as shown below can happen. main traffic_monitor_thread ==== ====================== show_transport() -> flockfile(stdout) stdio_hijack_init() -> stdout = open_memstream(log_buf, log_cnt); ... env.subtest_state->stdout_saved = stdout; ... funlockfile(stdout) stdio_restore_cleanup() -> fclose(env.subtest_state->stdout_saved); After the traffic monitor thread lock stdout, A new memstream can be assigned to stdout by the main thread. Therefore, the traffic monitor thread later will not be able to unlock the original stdout. As the main thread tries to access the old stdout, it will hang indefinitely as it is still locked by the traffic monitor thread. The deadlock can be reproduced by running test_progs repeatedly with traffic monitor enabled: for ((i=1;i<=100;i++)); do ./test_progs -a flow_dissector_skb* -m '*' done Fix this by only calling printf once and remove flockfile()/funlockfile(). Signed-off-by: Amery Hung <ameryhung(a)gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau(a)kernel.org> Link: https://patch.msgid.link/20250213233217.553258-1-ameryhung@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/network_helpers.c | 33 ++++++++----------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 27784946b01b8..af0ee70a53f9f 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -771,12 +771,13 @@ static const char *pkt_type_str(u16 pkt_type) return "Unknown"; } +#define MAX_FLAGS_STRLEN 21 /* Show the information of the transport layer in the packet */ static void show_transport(const u_char *packet, u16 len, u32 ifindex, const char *src_addr, const char *dst_addr, u16 proto, bool ipv6, u8 pkt_type) { - char *ifname, _ifname[IF_NAMESIZE]; + char *ifname, _ifname[IF_NAMESIZE], flags[MAX_FLAGS_STRLEN] = ""; const char *transport_str; u16 src_port, dst_port; struct udphdr *udp; @@ -817,29 +818,21 @@ static void show_transport(const u_char *packet, u16 len, u32 ifindex, /* TCP or UDP*/ - flockfile(stdout); + if (proto == IPPROTO_TCP) + snprintf(flags, MAX_FLAGS_STRLEN, "%s%s%s%s", + tcp->fin ? ", FIN" : "", + tcp->syn ? ", SYN" : "", + tcp->rst ? ", RST" : "", + tcp->ack ? ", ACK" : ""); + if (ipv6) - printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d", + printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); + dst_addr, dst_port, transport_str, len, flags); else - printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d", + printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); - - if (proto == IPPROTO_TCP) { - if (tcp->fin) - printf(", FIN"); - if (tcp->syn) - printf(", SYN"); - if (tcp->rst) - printf(", RST"); - if (tcp->ack) - printf(", ACK"); - } - - printf("\n"); - funlockfile(stdout); + dst_addr, dst_port, transport_str, len, flags); } static void show_ipv6_packet(const u_char *packet, u32 ifindex, u8 pkt_type) -- 2.39.5

3 weeks, 4 days

1
0
0 0

[PATCH AUTOSEL 6.14 17/23] selftests/bpf: Fix cap_enable_effective() return code

by Sasha Levin

From: Feng Yang <yangfeng(a)kylinos.cn> [ Upstream commit 339c1f8ea11cc042c30c315c1a8f61e4b8a90117 ] The caller of cap_enable_effective() expects negative error code. Fix it. Before: failed to restore CAP_SYS_ADMIN: -1, Unknown error -1 After: failed to restore CAP_SYS_ADMIN: -3, No such process failed to restore CAP_SYS_ADMIN: -22, Invalid argument Signed-off-by: Feng Yang <yangfeng(a)kylinos.cn> Acked-by: Eduard Zingerman <eddyz87(a)gmail.com> Link: https://lore.kernel.org/r/20250305022234.44932-1-yangfeng59949@163.com Signed-off-by: Alexei Starovoitov <ast(a)kernel.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/cap_helpers.c | 8 ++++---- tools/testing/selftests/bpf/cap_helpers.h | 1 + tools/testing/selftests/bpf/prog_tests/verifier.c | 4 ++-- tools/testing/selftests/bpf/test_loader.c | 6 +++--- 4 files changed, 10 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/bpf/cap_helpers.c b/tools/testing/selftests/bpf/cap_helpers.c index d5ac507401d7c..98f840c3a38f7 100644 --- a/tools/testing/selftests/bpf/cap_helpers.c +++ b/tools/testing/selftests/bpf/cap_helpers.c @@ -19,7 +19,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -32,7 +32,7 @@ int cap_enable_effective(__u64 caps, __u64 *old_caps) data[1].effective |= cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } @@ -49,7 +49,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) err = capget(&hdr, data); if (err) - return err; + return -errno; if (old_caps) *old_caps = (__u64)(data[1].effective) << 32 | data[0].effective; @@ -61,7 +61,7 @@ int cap_disable_effective(__u64 caps, __u64 *old_caps) data[1].effective &= ~cap1; err = capset(&hdr, data); if (err) - return err; + return -errno; return 0; } diff --git a/tools/testing/selftests/bpf/cap_helpers.h b/tools/testing/selftests/bpf/cap_helpers.h index 6d163530cb0fd..8dcb28557f762 100644 --- a/tools/testing/selftests/bpf/cap_helpers.h +++ b/tools/testing/selftests/bpf/cap_helpers.h @@ -4,6 +4,7 @@ #include <linux/types.h> #include <linux/capability.h> +#include <errno.h> #ifndef CAP_PERFMON #define CAP_PERFMON 38 diff --git a/tools/testing/selftests/bpf/prog_tests/verifier.c b/tools/testing/selftests/bpf/prog_tests/verifier.c index 8a0e1ff8a2dc6..ecc320e045513 100644 --- a/tools/testing/selftests/bpf/prog_tests/verifier.c +++ b/tools/testing/selftests/bpf/prog_tests/verifier.c @@ -121,7 +121,7 @@ static void run_tests_aux(const char *skel_name, /* test_verifier tests are executed w/o CAP_SYS_ADMIN, do the same here */ err = cap_disable_effective(1ULL << CAP_SYS_ADMIN, &old_caps); if (err) { - PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); return; } @@ -131,7 +131,7 @@ static void run_tests_aux(const char *skel_name, err = cap_enable_effective(old_caps, NULL); if (err) - PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore CAP_SYS_ADMIN: %i, %s\n", err, strerror(-err)); } #define RUN(skel) run_tests_aux(#skel, skel##__elf_bytes, NULL) diff --git a/tools/testing/selftests/bpf/test_loader.c b/tools/testing/selftests/bpf/test_loader.c index 53b06647cf57d..8a403e5aa3145 100644 --- a/tools/testing/selftests/bpf/test_loader.c +++ b/tools/testing/selftests/bpf/test_loader.c @@ -773,7 +773,7 @@ static int drop_capabilities(struct cap_state *caps) err = cap_disable_effective(caps_to_drop, &caps->old_caps); if (err) { - PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to drop capabilities: %i, %s\n", err, strerror(-err)); return err; } @@ -790,7 +790,7 @@ static int restore_capabilities(struct cap_state *caps) err = cap_enable_effective(caps->old_caps, NULL); if (err) - PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to restore capabilities: %i, %s\n", err, strerror(-err)); caps->initialized = false; return err; } @@ -959,7 +959,7 @@ void run_subtest(struct test_loader *tester, if (subspec->caps) { err = cap_enable_effective(subspec->caps, NULL); if (err) { - PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(err)); + PRINT_FAIL("failed to set capabilities: %i, %s\n", err, strerror(-err)); goto subtest_cleanup; } } -- 2.39.5

3 weeks, 4 days

1
0
0 0

[PATCH AUTOSEL 6.14 02/23] selftests/bpf: Fix stdout race condition in traffic monitor

by Sasha Levin

From: Amery Hung <ameryhung(a)gmail.com> [ Upstream commit b99f27e90268b1a814c13f8bd72ea1db448ea257 ] Fix a race condition between the main test_progs thread and the traffic monitoring thread. The traffic monitor thread tries to print a line using multiple printf and use flockfile() to prevent the line from being torn apart. Meanwhile, the main thread doing io redirection can reassign or close stdout when going through tests. A deadlock as shown below can happen. main traffic_monitor_thread ==== ====================== show_transport() -> flockfile(stdout) stdio_hijack_init() -> stdout = open_memstream(log_buf, log_cnt); ... env.subtest_state->stdout_saved = stdout; ... funlockfile(stdout) stdio_restore_cleanup() -> fclose(env.subtest_state->stdout_saved); After the traffic monitor thread lock stdout, A new memstream can be assigned to stdout by the main thread. Therefore, the traffic monitor thread later will not be able to unlock the original stdout. As the main thread tries to access the old stdout, it will hang indefinitely as it is still locked by the traffic monitor thread. The deadlock can be reproduced by running test_progs repeatedly with traffic monitor enabled: for ((i=1;i<=100;i++)); do ./test_progs -a flow_dissector_skb* -m '*' done Fix this by only calling printf once and remove flockfile()/funlockfile(). Signed-off-by: Amery Hung <ameryhung(a)gmail.com> Signed-off-by: Martin KaFai Lau <martin.lau(a)kernel.org> Link: https://patch.msgid.link/20250213233217.553258-1-ameryhung@gmail.com Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- tools/testing/selftests/bpf/network_helpers.c | 33 ++++++++----------- 1 file changed, 13 insertions(+), 20 deletions(-) diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 80844a5fb1fee..95e943270f359 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -771,12 +771,13 @@ static const char *pkt_type_str(u16 pkt_type) return "Unknown"; } +#define MAX_FLAGS_STRLEN 21 /* Show the information of the transport layer in the packet */ static void show_transport(const u_char *packet, u16 len, u32 ifindex, const char *src_addr, const char *dst_addr, u16 proto, bool ipv6, u8 pkt_type) { - char *ifname, _ifname[IF_NAMESIZE]; + char *ifname, _ifname[IF_NAMESIZE], flags[MAX_FLAGS_STRLEN] = ""; const char *transport_str; u16 src_port, dst_port; struct udphdr *udp; @@ -817,29 +818,21 @@ static void show_transport(const u_char *packet, u16 len, u32 ifindex, /* TCP or UDP*/ - flockfile(stdout); + if (proto == IPPROTO_TCP) + snprintf(flags, MAX_FLAGS_STRLEN, "%s%s%s%s", + tcp->fin ? ", FIN" : "", + tcp->syn ? ", SYN" : "", + tcp->rst ? ", RST" : "", + tcp->ack ? ", ACK" : ""); + if (ipv6) - printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d", + printf("%-7s %-3s IPv6 %s.%d > %s.%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); + dst_addr, dst_port, transport_str, len, flags); else - printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d", + printf("%-7s %-3s IPv4 %s:%d > %s:%d: %s, length %d%s\n", ifname, pkt_type_str(pkt_type), src_addr, src_port, - dst_addr, dst_port, transport_str, len); - - if (proto == IPPROTO_TCP) { - if (tcp->fin) - printf(", FIN"); - if (tcp->syn) - printf(", SYN"); - if (tcp->rst) - printf(", RST"); - if (tcp->ack) - printf(", ACK"); - } - - printf("\n"); - funlockfile(stdout); + dst_addr, dst_port, transport_str, len, flags); } static void show_ipv6_packet(const u_char *packet, u32 ifindex, u8 pkt_type) -- 2.39.5

3 weeks, 4 days

1
0
0 0

[PATCH net-next] net/selftests: Add loopback link local route for self-connect

by Dmitry Safonov via B4 Relay

From: Dmitry Safonov <0x7f454c46(a)gmail.com> self-connect-ipv6 got slightly flaky on netdev: > # timeout set to 120 > # selftests: net/tcp_ao: self-connect_ipv6 > # 1..5 > # # 708[lib/setup.c:250] rand seed 1742872572 > # TAP version 13 > # # 708[lib/proc.c:213] Snmp6 Ip6OutNoRoutes: 0 => 1 > # not ok 1 # error 708[self-connect.c:70] failed to connect() > # ok 2 No unexpected trace events during the test run > # # Planned tests != run tests (5 != 2) > # # Totals: pass:1 fail:0 xfail:0 xpass:0 skip:0 error:1 > ok 1 selftests: net/tcp_ao: self-connect_ipv6 I can not reproduce it on my machines, but judging by "Ip6OutNoRoutes" there is no route to the local_addr (::1). Looking at the kernel code, I see that kernel does add link-local address automatically in init_loopback(), but that is called from ipv6 notifier block. So, in turn the userspace that brought up the loopback interface may see rtnetlink ACK earlier than addrconf_notify() does it's job (at least, on a slow VM such as netdev). Probably, for ipv4 it's the same, judging by inetdev_event(). The fix is quite simple: set the link-local route straight after bringing the loopback interface. That will make it synchronous. Signed-off-by: Dmitry Safonov <0x7f454c46(a)gmail.com> --- Sorry to send this during the merge window, it's a test stability fix. It seems that netdev build bot has hit the issue a couple of times, but seems not hitting it constantly at this moment: https://netdev.bots.linux.dev/flakes.html?br-cnt=150&tn-needle=tcp-ao I'm marking it net-next, so that build bot carries it until the merge closes. If it's not fine, I can re-send it after the merge window. --- tools/testing/selftests/net/tcp_ao/self-connect.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/net/tcp_ao/self-connect.c b/tools/testing/selftests/net/tcp_ao/self-connect.c index 73b2f2276f3f5410aaa74bede7f366f81761bd6e..2c73bea698a677f9aedd7bec28f6e7fee7845d2e 100644 --- a/tools/testing/selftests/net/tcp_ao/self-connect.c +++ b/tools/testing/selftests/net/tcp_ao/self-connect.c @@ -16,6 +16,9 @@ static void __setup_lo_intf(const char *lo_intf, if (link_set_up(lo_intf)) test_error("Failed to bring %s up", lo_intf); + + if (ip_route_add(lo_intf, TEST_FAMILY, local_addr, local_addr)) + test_error("Failed to add a local route %s", lo_intf); } static void setup_lo_intf(const char *lo_intf) --- base-commit: 1a9239bb4253f9076b5b4b2a1a4e8d7defd77a95 change-id: 20250402-tcp-ao-selfconnect-flake-e0aabc03c076 Best regards, -- Dmitry Safonov <0x7f454c46(a)gmail.com>

3 weeks, 4 days

2
1
0 0

[PATCH bpf-next 00/11] bpf: Mitigate Spectre v1 using barriers

by Luis Gerhorst

This improves the expressiveness of unprivileged BPF by inserting speculation barriers instead of rejecting the programs. The approach was previously presented at LPC'24 [1] and RAID'24 [2]. To mitigate the Spectre v1 (PHT) vulnerability, the kernel rejects potentially-dangerous unprivileged BPF programs as of commit 9183671af6db ("bpf: Fix leakage under speculation on mispredicted branches"). In [2], we have analyzed 364 object files from open source projects (Linux Samples and Selftests, BCC, Loxilb, Cilium, libbpf Examples, Parca, and Prevail) and found that this affects 31% to 54% of programs. To resolve this in the majority of cases this patchset adds a fall-back for mitigating Spectre v1 using speculation barriers. The kernel still optimistically attempts to verify all speculative paths but uses speculation barriers against v1 when unsafe behavior is detected. This allows for more programs to be accepted without disabling the BPF Spectre mitigations (e.g., by setting cpu_mitigations_off()). In [1] we have measured the overhead of this approach relative to having mitigations off and including the upstream Spectre v4 mitigations. For event tracing and stack-sampling profilers, we found that mitigations increase BPF program execution time by 0% to 62%. For the Loxilb network load balancer, we have measured a 14% slowdown in SCTP performance but no significant slowdown for TCP. This overhead only applies to programs that were previously rejected. I reran the expressiveness-evaluation with v6.14 and made sure the main results still match those from [1] and [2] (which used v6.5). Main design decisions are: * Do not use separate bytecode insns for v1 and v4 barriers. This simplifies the verifier significantly and has the only downside that performance on PowerPC is not as high as it could be. * Allow archs to still disable v1/v4 mitigations separately by setting bpf_jit_bypass_spec_v1/v4(). This has the benefit that archs can benefit from improved BPF expressiveness / performance if they are not vulnerable (e.g., ARM64 for v4 in the kernel). * Do not remove the empty BPF_NOSPEC implementation for backends for which it is unknown whether they are vulnerable to Spectre v1. [1] https://lpc.events/event/18/contributions/1954/ ("Mitigating Spectre-PHT using Speculation Barriers in Linux eBPF") [2] https://arxiv.org/pdf/2405.00078 ("VeriFence: Lightweight and Precise Spectre Defenses for Untrusted Linux Kernel Extensions") Changes: * RFC -> v1: - rebase to bpf-next-250313 - tests: mark expected successes/new errors - add bpt_jit_bypass_spec_v1/v4() to avoid #ifdef in bpf_bypass_spec_v1/v4() - ensure that nospec with v1-support is implemented for archs for which GCC supports speculation barriers, except for MIPS - arm64: emit speculation barrier - powerpc: change nospec to include v1 barrier - discuss potential security (archs that do not impl. BPF nospec) and performance (only PowerPC) regressions RFC: https://lore.kernel.org/bpf/20250224203619.594724-1-luis.gerhorst@fau.de/ Luis Gerhorst (11): bpf: Move insn if/else into do_check_insn() bpf: Return -EFAULT on misconfigurations bpf: Return -EFAULT on internal errors bpf, arm64, powerpc: Add bpf_jit_bypass_spec_v1/v4() bpf, arm64, powerpc: Change nospec to include v1 barrier bpf: Rename sanitize_stack_spill to nospec_result bpf: Fall back to nospec for Spectre v1 bpf: Allow nospec-protected var-offset stack access bpf: Return PTR_ERR from push_stack() bpf: Fall back to nospec for sanitization-failures bpf: Fall back to nospec for spec path verification arch/arm64/net/bpf_jit.h | 5 + arch/arm64/net/bpf_jit_comp.c | 28 +- arch/powerpc/net/bpf_jit_comp64.c | 79 +- include/linux/bpf.h | 11 +- include/linux/bpf_verifier.h | 3 +- include/linux/filter.h | 2 +- kernel/bpf/core.c | 32 +- kernel/bpf/verifier.c | 723 ++++++++++-------- .../selftests/bpf/progs/verifier_and.c | 3 +- .../selftests/bpf/progs/verifier_bounds.c | 35 +- .../bpf/progs/verifier_bounds_deduction.c | 43 +- .../selftests/bpf/progs/verifier_map_ptr.c | 12 +- .../selftests/bpf/progs/verifier_movsx.c | 6 +- .../selftests/bpf/progs/verifier_unpriv.c | 3 +- .../bpf/progs/verifier_value_ptr_arith.c | 50 +- .../selftests/bpf/verifier/dead_code.c | 3 +- tools/testing/selftests/bpf/verifier/jmp32.c | 33 +- tools/testing/selftests/bpf/verifier/jset.c | 10 +- 18 files changed, 630 insertions(+), 451 deletions(-) base-commit: 46d38f489ef02175dcff1e03a849c226eb0729a6 -- 2.48.1

3 weeks, 4 days

3
22
0 0

[PATCH v8 00/10] Basic SEV-SNP Selftests

by Pratik R. Sampat

This patch series extends the sev_init2 and the sev_smoke test to exercise the SEV-SNP VM launch workflow. Primarily, it introduces the architectural defines, its support in the SEV library and extends the tests to interact with the SEV-SNP ioctl() wrappers. Patch 1 - Do not advertise SNP on initialization failure Patch 2 - SNP test for KVM_SEV_INIT2 Patch 3 - Add vmgexit helper Patch 4 - Add SMT control interface helper Patch 5 - Replace assert() with TEST_ASSERT_EQ() Patch 6 - Introduce SEV+ VM type check Patch 7 - SNP iotcl() plumbing for the SEV library Patch 8 - Force set GUEST_MEMFD for SNP Patch 9 - Cleanups of smoke test - Decouple policy from type Patch 10 - SNP smoke test The series is based on git.kernel.org/pub/scm/virt/kvm/kvm.git next v7..v8: * Dropped exporting the SNP initialized API from ccp to KVM. Instead call SNP_PLATFORM_STATUS within KVM to query the initialization. (Tom) While it may be cheaper to query sev->snp_initialized from ccp, making the SNP platform call within KVM does away with any dependencies. v6..v7: https://lore.kernel.org/kvm/20250221210200.244405-7-prsampat@amd.com/ Based on comments from Sean - * Replaced FW check with sev->snp_initialized * Dropped the patch which removes SEV+ KVM advertisement if INIT fails. This should be now be resolved by the combination of the patches [1,2] from Ashish. * Change vmgexit to an inline function * Export SMT control parsing interface to kvm_util Note: hyperv_cpuid KST only compile tested * Replace assert() with TEST_ASSERT_EQ() within SEV library * Define KVM_SEV_PAGE_TYPE_INVALID for SEV call of encrypt_region() * Parameterize encrypt_region() to include privatize_region() * Deduplication of sev test calls between SEV,SEV-ES and SNP * Removed FW version tests for SNP * Included testing of SNP_POLICY_DBG * Dropped most tags from patches that have been changed or indirectly affected [1] https://lore.kernel.org/all/d6d08c6b-9602-4f3d-92c2-8db6d50a1b92@amd.com [2] https://lore.kernel.org/all/f78ddb64087df27e7bcb1ae0ab53f55aa0804fab.173922… v5..v6: https://lore.kernel.org/kvm/ab433246-e97c-495b-ab67-b0cb1721fb99@amd.com/ * Rename is_sev_platform_init to sev_fw_initialized (Nikunj) * Rename KVM CPU feature X86_FEATURE_SNP to X86_FEATURE_SEV_SNP (Nikunj) * Collected Tags from Nikunj, Pankaj, Srikanth. v4..v5: https://lore.kernel.org/kvm/8e7d8172-879e-4a28-8438-343b1c386ec9@amd.com/ * Introduced a check to disable advertising support for SEV, SEV-ES and SNP when platform initialization fails (Nikunj) * Remove the redundant SNP check within is_sev_vm() (Nikunj) * Cleanup of the encrypt_region flow for better readability (Nikunj) * Refactor paths to use the canonical $(ARCH) to rebase for kvm/next v3..v4: https://lore.kernel.org/kvm/20241114234104.128532-1-pratikrajesh.sampat@amd… * Remove SNP FW API version check in the test and ensure the KVM capability advertises the presence of the feature. Retain the minimum version definitions to exercise these API versions in the smoke test * Retained only the SNP smoke test and SNP_INIT2 test * The SNP architectural defined merged with SNP_INIT2 test patch * SNP shutdown merged with SNP smoke test patch * Add SEV VM type check to abstract comparisons and reduce clutter * Define a SNP default policy which sets bits based on the presence of SMT * Decouple privatization and encryption for it to be SNP agnostic * Assert for only positive tests using vm_ioctl() * Dropped tested-by tags In summary - based on comments from Sean, I have primarily reduced the scope of this patch series to focus on breaking down the SNP smoke test patch (v3 - patch2) to first introduce SEV-SNP support and use this interface to extend the sev_init2 and the sev_smoke test. The rest of the v3 patchset that introduces ioctl, pre fault, fallocate and negative tests, will be re-worked and re-introduced subsequently in future patch series post addressing the issues discussed. v2..v3: https://lore.kernel.org/kvm/20240905124107.6954-1-pratikrajesh.sampat@amd.c… * Remove the assignments for the prefault and fallocate test type enums. * Fix error message for sev launch measure and finish. * Collect tested-by tags [Peter, Srikanth] Pratik R. Sampat (10): KVM: SEV: Disable SEV-SNP support on initialization failure KVM: selftests: SEV-SNP test for KVM_SEV_INIT2 KVM: selftests: Add vmgexit helper KVM: selftests: Add SMT control state helper KVM: selftests: Replace assert() with TEST_ASSERT_EQ() KVM: selftests: Introduce SEV VM type check KVM: selftests: Add library support for interacting with SNP KVM: selftests: Force GUEST_MEMFD flag for SNP VM type KVM: selftests: Abstractions for SEV to decouple policy from type KVM: selftests: Add a basic SEV-SNP smoke test arch/x86/include/uapi/asm/kvm.h | 1 + arch/x86/kvm/svm/sev.c | 30 +++++- tools/arch/x86/include/uapi/asm/kvm.h | 1 + .../testing/selftests/kvm/include/kvm_util.h | 35 +++++++ .../selftests/kvm/include/x86/processor.h | 1 + tools/testing/selftests/kvm/include/x86/sev.h | 42 ++++++++- tools/testing/selftests/kvm/lib/kvm_util.c | 7 +- .../testing/selftests/kvm/lib/x86/processor.c | 4 +- tools/testing/selftests/kvm/lib/x86/sev.c | 93 +++++++++++++++++-- .../testing/selftests/kvm/x86/hyperv_cpuid.c | 19 ---- .../selftests/kvm/x86/sev_init2_tests.c | 13 +++ .../selftests/kvm/x86/sev_smoke_test.c | 75 +++++++++------ 12 files changed, 261 insertions(+), 60 deletions(-) -- 2.43.0

3 weeks, 4 days

2
12
0 0

[PATCH v2 0/5] KVM: guest_memfd: support for uffd minor

by Nikita Kalyazin

This series is built on top of Fuad's v7 "mapping guest_memfd backed memory at the host" [1]. With James's KVM userfault [2], it is possible to handle stage-2 faults in guest_memfd in userspace. However, KVM itself also triggers faults in guest_memfd in some cases, for example: PV interfaces like kvmclock, PV EOI and page table walking code when fetching the MMIO instruction on x86. It was agreed in the guest_memfd upstream call on 23 Jan 2025 [3] that KVM would be accessing those pages via userspace page tables. In order for such faults to be handled in userspace, guest_memfd needs to support userfaultfd. Changes since v1 [4]: - James, Peter: implement a full minor trap instead of a hybrid missing/minor trap - James, Peter: to avoid shmem- and guest_memfd-specific code in the UFFDIO_CONTINUE implementation make it generic by calling vm_ops->fault() While generalising UFFDIO_CONTINUE implementation helped avoid guest_memfd-specific code in mm/userfaulfd, userfaultfd still needs access to KVM code to be able to verify the VMA type when handling UFFDIO_REGISTER_MODE_MINOR, so I used a similar approach to what Fuad did for now [5]. In v1, Peter was mentioning a potential for eliminating taking a folio lock [6]. I did not implement that, but according to my testing, the performance of shmem minor fault handling stayed the same after the migration to calling vm_ops->fault() (tested on an x86). Before: ./demand_paging_test -u MINOR -s shmem Random seed: 0x6b8b4567 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory: [0x3fffbffff000, 0x3ffffffff000) Finished creating vCPUs and starting uffd threads Started all vCPUs All vCPU threads joined Total guest execution time: 10.979277020s Per-vcpu demand paging rate: 23876.253375 pgs/sec/vcpu Overall demand paging rate: 23876.253375 pgs/sec After: ./demand_paging_test -u MINOR -s shmem Random seed: 0x6b8b4567 Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages guest physical test memory: [0x3fffbffff000, 0x3ffffffff000) Finished creating vCPUs and starting uffd threads Started all vCPUs All vCPU threads joined Total guest execution time: 10.978893504s Per-vcpu demand paging rate: 23877.087423 pgs/sec/vcpu Overall demand paging rate: 23877.087423 pgs/sec Nikita [1] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/ [2] https://lore.kernel.org/kvm/20250109204929.1106563-1-jthoughton@google.com/… [3] https://docs.google.com/document/d/1M6766BzdY1Lhk7LiR5IqVR8B8mG3cr-cxTxOrAo… [4] https://lore.kernel.org/kvm/20250303133011.44095-1-kalyazin@amazon.com/T/ [5] https://lore.kernel.org/kvm/20250318161823.4005529-1-tabba@google.com/T/#Z2… [6] https://lore.kernel.org/kvm/20250303133011.44095-1-kalyazin@amazon.com/T/#m… Nikita Kalyazin (5): mm: userfaultfd: generic continue for non hugetlbfs KVM: guest_memfd: add kvm_gmem_vma_is_gmem mm: userfaultfd: allow to register continue for guest_memfd KVM: guest_memfd: add support for userfaultfd minor KVM: selftests: test userfaultfd minor for guest_memfd include/linux/mm_types.h | 3 + include/linux/userfaultfd_k.h | 13 ++- mm/hugetlb.c | 2 +- mm/shmem.c | 3 +- mm/userfaultfd.c | 25 +++-- .../testing/selftests/kvm/guest_memfd_test.c | 94 +++++++++++++++++++ virt/kvm/guest_memfd.c | 15 +++ virt/kvm/kvm_mm.h | 1 + 8 files changed, 146 insertions(+), 10 deletions(-) base-commit: 3cc51efc17a2c41a480eed36b31c1773936717e0 -- 2.47.1

3 weeks, 4 days

2
11
0 0

2025

2024

2023

2022

2021

2020

2019

2018

2017

Linux-kselftest-mirror April 2025