- Linux-stable-mirror - lists.linaro.org

[PATCH v2] drm: Fix potential null pointer dereference issues in drm_managed.c

by Haoxiang Li

Add check for the return value of kstrdup_const() in drm_managed.c to prevent potential null pointer dereference. Fixes: c6603c740e0e ("drm: add managed resources tied to drm_device") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <haoxiang_li2024(a)163.com> --- Changes in v2: - Modify a fix error. Thanks, Dmitry! --- drivers/gpu/drm/drm_managed.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c index cc4c463daae7..e34b8dcde48c 100644 --- a/drivers/gpu/drm/drm_managed.c +++ b/drivers/gpu/drm/drm_managed.c @@ -151,6 +151,11 @@ int __drmm_add_action(struct drm_device *dev, } dr->node.name = kstrdup_const(name, GFP_KERNEL); + if (!dr->node.name) { + kfree(dr); + return -ENOMEM; + } + if (data) { void_ptr = (void **)&dr->data; *void_ptr = data; @@ -236,6 +241,10 @@ void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp) return NULL; } dr->node.name = kstrdup_const("kmalloc", gfp); + if (!dr->node.name) { + kfree(dr); + return NULL; + } add_dr(dev, dr); -- 2.25.1

3 months, 3 weeks

2
1
0 0

[PATCH v5] mm/slub: avoid accessing metadata when pointer is invalid in object_err()

by Li Qiong

object_err() reports details of an object for further debugging, such as the freelist pointer, redzone, etc. However, if the pointer is invalid, attempting to access object metadata can lead to a crash since it does not point to a valid object. In case check_valid_pointer() returns false for the pointer, only print the pointer value and skip accessing metadata. Fixes: 81819f0fc828 ("SLUB core") Cc: <stable(a)vger.kernel.org> Signed-off-by: Li Qiong <liqiong(a)nfschina.com> --- v2: - rephrase the commit message, add comment for object_err(). v3: - check object pointer in object_err(). v4: - restore changes in alloc_consistency_checks(). v5: - rephrase message, fix code style. --- mm/slub.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 31e11ef256f9..b3eff1476c85 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1104,7 +1104,12 @@ static void object_err(struct kmem_cache *s, struct slab *slab, return; slab_bug(s, reason); - print_trailer(s, slab, object); + if (!check_valid_pointer(s, slab, object)) { + print_slab_info(slab); + pr_err("Invalid pointer 0x%p\n", object); + } else { + print_trailer(s, slab, object); + } add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); WARN_ON(1); -- 2.30.2

3 months, 3 weeks

3
3
0 0

[PATCH v2] memstick: Fix deadlock by moving removing flag earlier

by Jiayi Li

The existing memstick core patch: commit 62c59a8786e6 ("memstick: Skip allocating card when removing host") sets host->removing in memstick_remove_host(),but still exists a critical time window where memstick_check can run after host->eject is set but before removing is set. In the rtsx_usb_ms driver, the problematic sequence is: rtsx_usb_ms_drv_remove: memstick_check: host->eject = true cancel_work_sync(handle_req) if(!host->removing) ... memstick_alloc_card() memstick_set_rw_addr() memstick_new_req() rtsx_usb_ms_request() if(!host->eject) skip schedule_work wait_for_completion() memstick_remove_host: [blocks indefinitely] host->removing = true flush_workqueue() [block] 1. rtsx_usb_ms_drv_remove sets host->eject = true 2. cancel_work_sync(&host->handle_req) runs 3. memstick_check work may be executed here <-- danger window 4. memstick_remove_host sets removing = 1 During this window (step 3), memstick_check calls memstick_alloc_card, which may indefinitely waiting for mrq_complete completion that will never occur because rtsx_usb_ms_request sees eject=true and skips scheduling work, memstick_set_rw_addr waits forever for completion. This causes a deadlock when memstick_remove_host tries to flush_workqueue, waiting for memstick_check to complete, while memstick_check is blocked waiting for mrq_complete completion. Fix this by setting removing=true at the start of rtsx_usb_ms_drv_remove, before any work cancellation. This ensures memstick_check will see the removing flag immediately and exit early, avoiding the deadlock. Fixes: 62c59a8786e6 ("memstick: Skip allocating card when removing host") Signed-off-by: Jiayi Li <lijiayi(a)kylinos.cn> Cc: stable(a)vger.kernel.org --- v1 -> v2: Added Cc: stable(a)vger.kernel.org --- drivers/memstick/core/memstick.c | 1 - drivers/memstick/host/rtsx_usb_ms.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/memstick/core/memstick.c b/drivers/memstick/core/memstick.c index 043b9ec756ff..95e65f4958f2 100644 --- a/drivers/memstick/core/memstick.c +++ b/drivers/memstick/core/memstick.c @@ -555,7 +555,6 @@ EXPORT_SYMBOL(memstick_add_host); */ void memstick_remove_host(struct memstick_host *host) { - host->removing = 1; flush_workqueue(workqueue); mutex_lock(&host->lock); if (host->card) diff --git a/drivers/memstick/host/rtsx_usb_ms.c b/drivers/memstick/host/rtsx_usb_ms.c index 3878136227e4..5b5e9354fb2e 100644 --- a/drivers/memstick/host/rtsx_usb_ms.c +++ b/drivers/memstick/host/rtsx_usb_ms.c @@ -812,6 +812,7 @@ static void rtsx_usb_ms_drv_remove(struct platform_device *pdev) int err; host->eject = true; + msh->removing = true; cancel_work_sync(&host->handle_req); cancel_delayed_work_sync(&host->poll_card); -- 2.47.1

3 months, 3 weeks

1
0
0 0

[PATCH AUTOSEL 5.4 01/28] usb: xhci: print xhci->xhc_state when queue_command failed

by Sasha Levin

From: Su Hui <suhui(a)nfschina.com> [ Upstream commit 7919407eca2ef562fa6c98c41cfdf6f6cdd69d92 ] When encounters some errors like these: xhci_hcd 0000:4a:00.2: xHCI dying or halted, can't queue_command xhci_hcd 0000:4a:00.2: FIXME: allocate a command ring segment usb usb5-port6: couldn't allocate usb_device It's hard to know whether xhc_state is dying or halted. So it's better to print xhc_state's value which can help locate the resaon of the bug. Signed-off-by: Su Hui <suhui(a)nfschina.com> Link: https://lore.kernel.org/r/20250725060117.1773770-1-suhui@nfschina.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: **Backport Status: YES** This commit is suitable for backporting to stable kernel trees for the following reasons: 1. **Enhanced Debugging for Real-World Issues**: The commit improves debugging of USB xHCI host controller failures by printing the actual `xhc_state` value when `queue_command` fails. The commit message shows real error messages users encounter ("xHCI dying or halted, can't queue_command"), demonstrating this is a real-world debugging problem. 2. **Minimal and Safe Change**: The change is extremely small and safe - it only modifies a debug print statement from: ```c xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n"); ``` to: ```c xhci_dbg(xhci, "xHCI dying or halted, can't queue_command. state: 0x%x\n", xhci->xhc_state); ``` 3. **No Functional Changes**: This is a pure diagnostic improvement. It doesn't change any logic, control flow, or data structures. It only adds the state value (0x%x format) to an existing debug message. 4. **Important for Troubleshooting**: The xHCI driver is critical for USB functionality, and when it fails with "dying or halted" states, knowing the exact state helps diagnose whether: - `XHCI_STATE_DYING` (0x1) - controller is dying - `XHCI_STATE_HALTED` (0x2) - controller is halted - Both states (0x3) - controller has both flags set This distinction is valuable for debugging hardware issues, driver bugs, or system problems. 5. **Zero Risk of Regression**: Adding a parameter to a debug print statement has no risk of introducing regressions. The worst case is the debug message prints the state value. 6. **Follows Stable Rules**: This meets stable kernel criteria as it: - Fixes a real debugging limitation - Is obviously correct - Has been tested (signed-off and accepted by Greg KH) - Is small (single line change) - Doesn't add new features, just improves existing diagnostics The commit helps system administrators and developers diagnose USB issues more effectively by providing the actual state value rather than just saying "dying or halted", making it a valuable debugging enhancement for stable kernels. drivers/usb/host/xhci-ring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 08b016864fc0..71b17a00d3ed 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -4076,7 +4076,8 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd, if ((xhci->xhc_state & XHCI_STATE_DYING) || (xhci->xhc_state & XHCI_STATE_HALTED)) { - xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n"); + xhci_dbg(xhci, "xHCI dying or halted, can't queue_command. state: 0x%x\n", + xhci->xhc_state); return -ESHUTDOWN; } -- 2.39.5

3 months, 3 weeks

1
27
0 0

[PATCH AUTOSEL 5.10 01/39] usb: xhci: print xhci->xhc_state when queue_command failed

by Sasha Levin

From: Su Hui <suhui(a)nfschina.com> [ Upstream commit 7919407eca2ef562fa6c98c41cfdf6f6cdd69d92 ] When encounters some errors like these: xhci_hcd 0000:4a:00.2: xHCI dying or halted, can't queue_command xhci_hcd 0000:4a:00.2: FIXME: allocate a command ring segment usb usb5-port6: couldn't allocate usb_device It's hard to know whether xhc_state is dying or halted. So it's better to print xhc_state's value which can help locate the resaon of the bug. Signed-off-by: Su Hui <suhui(a)nfschina.com> Link: https://lore.kernel.org/r/20250725060117.1773770-1-suhui@nfschina.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: **Backport Status: YES** This commit is suitable for backporting to stable kernel trees for the following reasons: 1. **Enhanced Debugging for Real-World Issues**: The commit improves debugging of USB xHCI host controller failures by printing the actual `xhc_state` value when `queue_command` fails. The commit message shows real error messages users encounter ("xHCI dying or halted, can't queue_command"), demonstrating this is a real-world debugging problem. 2. **Minimal and Safe Change**: The change is extremely small and safe - it only modifies a debug print statement from: ```c xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n"); ``` to: ```c xhci_dbg(xhci, "xHCI dying or halted, can't queue_command. state: 0x%x\n", xhci->xhc_state); ``` 3. **No Functional Changes**: This is a pure diagnostic improvement. It doesn't change any logic, control flow, or data structures. It only adds the state value (0x%x format) to an existing debug message. 4. **Important for Troubleshooting**: The xHCI driver is critical for USB functionality, and when it fails with "dying or halted" states, knowing the exact state helps diagnose whether: - `XHCI_STATE_DYING` (0x1) - controller is dying - `XHCI_STATE_HALTED` (0x2) - controller is halted - Both states (0x3) - controller has both flags set This distinction is valuable for debugging hardware issues, driver bugs, or system problems. 5. **Zero Risk of Regression**: Adding a parameter to a debug print statement has no risk of introducing regressions. The worst case is the debug message prints the state value. 6. **Follows Stable Rules**: This meets stable kernel criteria as it: - Fixes a real debugging limitation - Is obviously correct - Has been tested (signed-off and accepted by Greg KH) - Is small (single line change) - Doesn't add new features, just improves existing diagnostics The commit helps system administrators and developers diagnose USB issues more effectively by providing the actual state value rather than just saying "dying or halted", making it a valuable debugging enhancement for stable kernels. drivers/usb/host/xhci-ring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 954cd962e113..c026e7cc0af1 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -4183,7 +4183,8 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd, if ((xhci->xhc_state & XHCI_STATE_DYING) || (xhci->xhc_state & XHCI_STATE_HALTED)) { - xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n"); + xhci_dbg(xhci, "xHCI dying or halted, can't queue_command. state: 0x%x\n", + xhci->xhc_state); return -ESHUTDOWN; } -- 2.39.5

3 months, 3 weeks

1
38
0 0

[PATCH AUTOSEL 5.15 01/44] usb: xhci: print xhci->xhc_state when queue_command failed

by Sasha Levin

From: Su Hui <suhui(a)nfschina.com> [ Upstream commit 7919407eca2ef562fa6c98c41cfdf6f6cdd69d92 ] When encounters some errors like these: xhci_hcd 0000:4a:00.2: xHCI dying or halted, can't queue_command xhci_hcd 0000:4a:00.2: FIXME: allocate a command ring segment usb usb5-port6: couldn't allocate usb_device It's hard to know whether xhc_state is dying or halted. So it's better to print xhc_state's value which can help locate the resaon of the bug. Signed-off-by: Su Hui <suhui(a)nfschina.com> Link: https://lore.kernel.org/r/20250725060117.1773770-1-suhui@nfschina.com Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: **Backport Status: YES** This commit is suitable for backporting to stable kernel trees for the following reasons: 1. **Enhanced Debugging for Real-World Issues**: The commit improves debugging of USB xHCI host controller failures by printing the actual `xhc_state` value when `queue_command` fails. The commit message shows real error messages users encounter ("xHCI dying or halted, can't queue_command"), demonstrating this is a real-world debugging problem. 2. **Minimal and Safe Change**: The change is extremely small and safe - it only modifies a debug print statement from: ```c xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n"); ``` to: ```c xhci_dbg(xhci, "xHCI dying or halted, can't queue_command. state: 0x%x\n", xhci->xhc_state); ``` 3. **No Functional Changes**: This is a pure diagnostic improvement. It doesn't change any logic, control flow, or data structures. It only adds the state value (0x%x format) to an existing debug message. 4. **Important for Troubleshooting**: The xHCI driver is critical for USB functionality, and when it fails with "dying or halted" states, knowing the exact state helps diagnose whether: - `XHCI_STATE_DYING` (0x1) - controller is dying - `XHCI_STATE_HALTED` (0x2) - controller is halted - Both states (0x3) - controller has both flags set This distinction is valuable for debugging hardware issues, driver bugs, or system problems. 5. **Zero Risk of Regression**: Adding a parameter to a debug print statement has no risk of introducing regressions. The worst case is the debug message prints the state value. 6. **Follows Stable Rules**: This meets stable kernel criteria as it: - Fixes a real debugging limitation - Is obviously correct - Has been tested (signed-off and accepted by Greg KH) - Is small (single line change) - Doesn't add new features, just improves existing diagnostics The commit helps system administrators and developers diagnose USB issues more effectively by providing the actual state value rather than just saying "dying or halted", making it a valuable debugging enhancement for stable kernels. drivers/usb/host/xhci-ring.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index cd94b0a4e021..626f02605192 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -4486,7 +4486,8 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd, if ((xhci->xhc_state & XHCI_STATE_DYING) || (xhci->xhc_state & XHCI_STATE_HALTED)) { - xhci_dbg(xhci, "xHCI dying or halted, can't queue_command\n"); + xhci_dbg(xhci, "xHCI dying or halted, can't queue_command. state: 0x%x\n", + xhci->xhc_state); return -ESHUTDOWN; } -- 2.39.5

3 months, 3 weeks

1
43
0 0

[PATCH v4] mm: slub: avoid deref of invalid free pointer in object_err()

by Li Qiong

For debugging, object_err() prints free pointer of the object. However, if object is a invalid pointer, dereferncing `object + s->offset` can lead to a crash. Therefore, add check_valid_pointer() for the object. Fixes: 81819f0fc828 ("SLUB core") Cc: <stable(a)vger.kernel.org> Signed-off-by: Li Qiong <liqiong(a)nfschina.com> --- v2: - rephrase the commit message, add comment for object_err(). v3: - check object pointer in object_err(). v4: - restore changes in alloc_consistency_checks(). --- mm/slub.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/mm/slub.c b/mm/slub.c index 31e11ef256f9..17b91e74f7d9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -1104,7 +1104,11 @@ static void object_err(struct kmem_cache *s, struct slab *slab, return; slab_bug(s, reason); - print_trailer(s, slab, object); + if (!check_valid_pointer(s, slab, object)) { + print_slab_info(slab); + pr_err("invalid object 0x%p\n", object); + } else + print_trailer(s, slab, object); add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); WARN_ON(1); -- 2.30.2

3 months, 3 weeks

2
1
0 0

[PATCH RESEND] drm: Fix potential null pointer dereference issues in drm_managed.c

by Haoxiang Li

Add check for the return value of kstrdup_const() in drm_managed.c to prevent potential null pointer dereference. Fixes: c6603c740e0e ("drm: add managed resources tied to drm_device") Cc: stable(a)vger.kernel.org Signed-off-by: Haoxiang Li <haoxiang_li2024(a)163.com> --- drivers/gpu/drm/drm_managed.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/gpu/drm/drm_managed.c b/drivers/gpu/drm/drm_managed.c index cc4c463daae7..368763d4c24e 100644 --- a/drivers/gpu/drm/drm_managed.c +++ b/drivers/gpu/drm/drm_managed.c @@ -151,6 +151,11 @@ int __drmm_add_action(struct drm_device *dev, } dr->node.name = kstrdup_const(name, GFP_KERNEL); + if (!dr->node.name) { + kfree(dr); + return -ENOMEM; + } + if (data) { void_ptr = (void **)&dr->data; *void_ptr = data; @@ -236,6 +241,10 @@ void *drmm_kmalloc(struct drm_device *dev, size_t size, gfp_t gfp) return NULL; } dr->node.name = kstrdup_const("kmalloc", gfp); + if (dr->node.name) { + kfree(dr); + return NULL; + } add_dr(dev, dr); -- 2.25.1

3 months, 3 weeks

3
2
0 0

[PATCH 0/4] i2c: rtl9300: Fix multi-byte I2C operations

by Sven Eckelmann

During the integration of the RTL8239 POE chip + its frontend MCU, it was noticed that multi-byte operations were basically broken in the current driver. Tests using SMBus Block Writes showed that the data (after the Wr + Ack marker) was mixed up on the wire. At first glance, it looked like an endianness problem. But for transfers were the number of count + data bytes was not divisible by 4, the last bytes were not looking like an endianness problem because they were were in the wrong order but not for example 0 - which would be the case for an endianness problem with 32 bit registers. At the end, it turned out to be a the way how i2c_write tried to add the bytes to the send registers. Each 32 bit register was used similar to a shift register - shifting the various bytes up the register while the next one is added to the least significant byte. But the I2C controller expects the first byte of the tranmission in the least significant byte of the first register. And the last byte (assuming it is a 16 byte transfer) in the most significant byte of the fourth register. While doing these tests, it was also observed that the count byte was missing from the SMBus Block Writes. The driver just removed them from the data->block (from the I2C subsystem). But the I2C controller DOES NOT automatically add this byte - for example by using the configured transmission length. The RTL8239 MCU is not actually an SMBus compliant device. Instead, it expects I2C Block Reads + I2C Block Writes. But according to the already identified bugs in the driver, it was clear that the I2C controller can simply be modified to not send the count byte for I2C_SMBUS_I2C_BLOCK_DATA. The receive part, just needs to write the content of the receive buffer to the correct position in data->block. While the on-wire formwat was now correct, reads were still not possible against the MCU (for the RTL8239 POE chip). It was always timing out because the 2ms were not enough for sending the read request and then receiving the 12 byte answer. These changes were originally submitted to OpenWrt. But there are plans to migrate OpenWrt to the upstream Linux driver. As result, the pull request was stopped and the changes were redone against this driver. Signed-off-by: Sven Eckelmann <sven(a)narfation.org> --- Harshal Gohel (2): i2c: rtl9300: Fix multi-byte I2C write i2c: rtl9300: Implement I2C block read and write Sven Eckelmann (2): i2c: rtl9300: Increase timeout for transfer polling i2c: rtl9300: Add missing count byte for SMBus Block Write drivers/i2c/busses/i2c-rtl9300.c | 43 +++++++++++++++++++++++++++++++++------- 1 file changed, 36 insertions(+), 7 deletions(-) --- base-commit: b9ddaa95fd283bce7041550ddbbe7e764c477110 change-id: 20250802-i2c-rtl9300-multi-byte-edaa1fb0872c Best regards, -- Sven Eckelmann <sven(a)narfation.org>

3 months, 3 weeks

2
7
0 0

[PATCH AUTOSEL 5.4 1/9] hfs: fix slab-out-of-bounds in hfs_bnode_read()

by Sasha Levin

From: Viacheslav Dubeyko <slava(a)dubeyko.com> [ Upstream commit a431930c9bac518bf99d6b1da526a7f37ddee8d8 ] This patch introduces is_bnode_offset_valid() method that checks the requested offset value. Also, it introduces check_and_correct_requested_length() method that checks and correct the requested length (if it is necessary). These methods are used in hfs_bnode_read(), hfs_bnode_write(), hfs_bnode_clear(), hfs_bnode_copy(), and hfs_bnode_move() with the goal to prevent the access out of allocated memory and triggering the crash. Signed-off-by: Viacheslav Dubeyko <slava(a)dubeyko.com> Link: https://lore.kernel.org/r/20250703214912.244138-1-slava@dubeyko.com Signed-off-by: Viacheslav Dubeyko <slava(a)dubeyko.com> Signed-off-by: Sasha Levin <sashal(a)kernel.org> --- LLM Generated explanations, may be completely bogus: **Backport Status: YES** This commit should definitely be backported to stable kernel trees. Here's my detailed analysis: ## Critical Security Fix This patch fixes a **critical security vulnerability** - a slab-out-of- bounds access that can lead to memory corruption and potentially local privilege escalation. The vulnerability exists in multiple HFS bnode operations: 1. **Affected Functions**: The patch adds bounds checking to `hfs_bnode_read()`, `hfs_bnode_write()`, `hfs_bnode_clear()`, `hfs_bnode_copy()`, and `hfs_bnode_move()` - all core operations for HFS B-tree node handling. 2. **Root Cause**: These functions previously accepted offset and length parameters without any validation, allowing reads/writes beyond allocated memory when processing malformed HFS filesystems. ## Nature of the Fix The fix is well-designed and minimal: 1. **Two validation functions added**: - `is_bnode_offset_valid()`: Ensures offset is within node boundaries - `check_and_correct_requested_length()`: Adjusts length to prevent out-of-bounds access 2. **Defensive programming**: The functions log errors but continue safely rather than crashing, which is appropriate for filesystem code. ## Backporting Criteria Met 1. **Fixes a real bug affecting users**: Yes - security vulnerability with CVE assignments 2. **Small and contained**: Yes - adds ~56 lines of validation code, no architectural changes 3. **Clear side effects**: Minimal - only adds safety checks, no functional changes 4. **No major architectural changes**: Correct - just adds input validation 5. **Critical subsystem**: Yes - filesystem security vulnerability 6. **Risk assessment**: Low risk - purely defensive checks that prevent invalid operations ## Additional Context - This is a **long-standing issue** (not a recent regression), making it even more important to backport - Similar fixes have been applied to HFS+ filesystem, showing this is a systematic issue - The vulnerability allows mounting malformed filesystems to trigger heap corruption - HFS is legacy but still supported for compatibility with older Mac systems The patch perfectly fits stable tree criteria: it's a critical security fix that's minimal, well-contained, and has very low risk of introducing regressions while addressing a serious vulnerability. fs/hfs/bnode.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/fs/hfs/bnode.c b/fs/hfs/bnode.c index 2251286cd83f..2039cb6d5f66 100644 --- a/fs/hfs/bnode.c +++ b/fs/hfs/bnode.c @@ -15,6 +15,48 @@ #include "btree.h" +static inline +bool is_bnode_offset_valid(struct hfs_bnode *node, int off) +{ + bool is_valid = off < node->tree->node_size; + + if (!is_valid) { + pr_err("requested invalid offset: " + "NODE: id %u, type %#x, height %u, " + "node_size %u, offset %d\n", + node->this, node->type, node->height, + node->tree->node_size, off); + } + + return is_valid; +} + +static inline +int check_and_correct_requested_length(struct hfs_bnode *node, int off, int len) +{ + unsigned int node_size; + + if (!is_bnode_offset_valid(node, off)) + return 0; + + node_size = node->tree->node_size; + + if ((off + len) > node_size) { + int new_len = (int)node_size - off; + + pr_err("requested length has been corrected: " + "NODE: id %u, type %#x, height %u, " + "node_size %u, offset %d, " + "requested_len %d, corrected_len %d\n", + node->this, node->type, node->height, + node->tree->node_size, off, len, new_len); + + return new_len; + } + + return len; +} + void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len) { struct page *page; @@ -23,6 +65,20 @@ void hfs_bnode_read(struct hfs_bnode *node, void *buf, int off, int len) int bytes_to_read; void *vaddr; + if (!is_bnode_offset_valid(node, off)) + return; + + if (len == 0) { + pr_err("requested zero length: " + "NODE: id %u, type %#x, height %u, " + "node_size %u, offset %d, len %d\n", + node->this, node->type, node->height, + node->tree->node_size, off, len); + return; + } + + len = check_and_correct_requested_length(node, off, len); + off += node->page_offset; pagenum = off >> PAGE_SHIFT; off &= ~PAGE_MASK; /* compute page offset for the first page */ @@ -83,6 +139,20 @@ void hfs_bnode_write(struct hfs_bnode *node, void *buf, int off, int len) { struct page *page; + if (!is_bnode_offset_valid(node, off)) + return; + + if (len == 0) { + pr_err("requested zero length: " + "NODE: id %u, type %#x, height %u, " + "node_size %u, offset %d, len %d\n", + node->this, node->type, node->height, + node->tree->node_size, off, len); + return; + } + + len = check_and_correct_requested_length(node, off, len); + off += node->page_offset; page = node->page[0]; @@ -108,6 +178,20 @@ void hfs_bnode_clear(struct hfs_bnode *node, int off, int len) { struct page *page; + if (!is_bnode_offset_valid(node, off)) + return; + + if (len == 0) { + pr_err("requested zero length: " + "NODE: id %u, type %#x, height %u, " + "node_size %u, offset %d, len %d\n", + node->this, node->type, node->height, + node->tree->node_size, off, len); + return; + } + + len = check_and_correct_requested_length(node, off, len); + off += node->page_offset; page = node->page[0]; @@ -124,6 +208,10 @@ void hfs_bnode_copy(struct hfs_bnode *dst_node, int dst, hfs_dbg(BNODE_MOD, "copybytes: %u,%u,%u\n", dst, src, len); if (!len) return; + + len = check_and_correct_requested_length(src_node, src, len); + len = check_and_correct_requested_length(dst_node, dst, len); + src += src_node->page_offset; dst += dst_node->page_offset; src_page = src_node->page[0]; @@ -143,6 +231,10 @@ void hfs_bnode_move(struct hfs_bnode *node, int dst, int src, int len) hfs_dbg(BNODE_MOD, "movebytes: %u,%u,%u\n", dst, src, len); if (!len) return; + + len = check_and_correct_requested_length(node, src, len); + len = check_and_correct_requested_length(node, dst, len); + src += node->page_offset; dst += node->page_offset; page = node->page[0]; -- 2.39.5

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