* FAILED: patch "[PATCH] xfs: fix out of bounds memory read error in symlink repair" failed to apply to 6.17-stable tree
@ 2025-11-24 13:25 gregkh
2025-11-24 17:45 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Sasha Levin
0 siblings, 1 reply; 4+ messages in thread
From: gregkh @ 2025-11-24 13:25 UTC (permalink / raw)
To: djwong, cem, hch; +Cc: stable
The patch below does not apply to the 6.17-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.17.y
git checkout FETCH_HEAD
git cherry-pick -x 678e1cc2f482e0985a0613ab4a5bf89c497e5acc
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2025112457-shining-trough-db05@gregkh' --subject-prefix 'PATCH 6.17.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 678e1cc2f482e0985a0613ab4a5bf89c497e5acc Mon Sep 17 00:00:00 2001
From: "Darrick J. Wong" <djwong@kernel.org>
Date: Wed, 12 Nov 2025 08:35:18 -0800
Subject: [PATCH] xfs: fix out of bounds memory read error in symlink repair
xfs/286 produced this report on my test fleet:
==================================================================
BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110
Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):
memcpy_orig+0x54/0x110
xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]
xrep_symlink_salvage+0x100/0x110 [xfs]
xrep_symlink+0x2e/0x80 [xfs]
xrep_attempt+0x61/0x1f0 [xfs]
xfs_scrub_metadata+0x34f/0x5c0 [xfs]
xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]
xfs_file_ioctl+0xe23/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128
allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):
xfs_init_local_fork+0x79/0xe0 [xfs]
xfs_iformat_local+0xa4/0x170 [xfs]
xfs_iformat_data_fork+0x148/0x180 [xfs]
xfs_inode_from_disk+0x2cd/0x480 [xfs]
xfs_iget+0x450/0xd60 [xfs]
xfs_bulkstat_one_int+0x6b/0x510 [xfs]
xfs_bulkstat_iwalk+0x1e/0x30 [xfs]
xfs_iwalk_ag_recs+0xdf/0x150 [xfs]
xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]
xfs_iwalk_ag+0x1dc/0x2f0 [xfs]
xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]
xfs_iwalk+0xa4/0xd0 [xfs]
xfs_bulkstat+0xfa/0x170 [xfs]
xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]
xfs_file_ioctl+0xbf2/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy) 3d744dd94e92690f00a04398d2bd8631dcef1954
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014
==================================================================
On further analysis, I realized that the second parameter to min() is
not correct. xfs_ifork::if_bytes is the size of the xfs_ifork::if_data
buffer. if_bytes can be smaller than the data fork size because:
(a) the forkoff code tries to keep the data area as large as possible
(b) for symbolic links, if_bytes is the ondisk file size + 1
(c) forkoff is always a multiple of 8.
Case in point: for a single-byte symlink target, forkoff will be
8 but the buffer will only be 2 bytes long.
In other words, the logic here is wrong and we walk off the end of the
incore buffer. Fix that.
Cc: stable@vger.kernel.org # v6.10
Fixes: 2651923d8d8db0 ("xfs: online repair of symbolic links")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
diff --git a/fs/xfs/scrub/symlink_repair.c b/fs/xfs/scrub/symlink_repair.c
index 5902398185a8..df629892462f 100644
--- a/fs/xfs/scrub/symlink_repair.c
+++ b/fs/xfs/scrub/symlink_repair.c
@@ -184,7 +184,7 @@ xrep_symlink_salvage_inline(
sc->ip->i_disk_size == 1 && old_target[0] == '?')
return 0;
- nr = min(XFS_SYMLINK_MAXLEN, xfs_inode_data_fork_size(ip));
+ nr = min(XFS_SYMLINK_MAXLEN, ifp->if_bytes);
memcpy(target_buf, ifp->if_data, nr);
return nr;
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy
2025-11-24 13:25 FAILED: patch "[PATCH] xfs: fix out of bounds memory read error in symlink repair" failed to apply to 6.17-stable tree gregkh
@ 2025-11-24 17:45 ` Sasha Levin
2025-11-24 17:45 ` [PATCH 6.17.y 2/2] xfs: fix out of bounds memory read error in symlink repair Sasha Levin
2025-11-26 22:39 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Darrick J. Wong
0 siblings, 2 replies; 4+ messages in thread
From: Sasha Levin @ 2025-11-24 17:45 UTC (permalink / raw)
To: stable
Cc: Marcelo Moreira, Dave Chinner, Christoph Hellwig, Carlos Maiolino,
Darrick J. Wong, Carlos Maiolino, Sasha Levin
From: Marcelo Moreira <marcelomoreira1905@gmail.com>
[ Upstream commit 33ddc796ecbd50cd6211aa9e9eddbf4567038b49 ]
The changes modernizes the code by aligning it with current kernel best
practices. It improves code clarity and consistency, as strncpy is deprecated
as explained in Documentation/process/deprecated.rst. This change does
not alter the functionality or introduce any behavioral changes.
Suggested-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Marcelo Moreira <marcelomoreira1905@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Stable-dep-of: 678e1cc2f482 ("xfs: fix out of bounds memory read error in symlink repair")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/xfs/scrub/symlink_repair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/xfs/scrub/symlink_repair.c b/fs/xfs/scrub/symlink_repair.c
index 953ce7be78dc2..5902398185a89 100644
--- a/fs/xfs/scrub/symlink_repair.c
+++ b/fs/xfs/scrub/symlink_repair.c
@@ -185,7 +185,7 @@ xrep_symlink_salvage_inline(
return 0;
nr = min(XFS_SYMLINK_MAXLEN, xfs_inode_data_fork_size(ip));
- strncpy(target_buf, ifp->if_data, nr);
+ memcpy(target_buf, ifp->if_data, nr);
return nr;
}
--
2.51.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH 6.17.y 2/2] xfs: fix out of bounds memory read error in symlink repair
2025-11-24 17:45 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Sasha Levin
@ 2025-11-24 17:45 ` Sasha Levin
2025-11-26 22:39 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Darrick J. Wong
1 sibling, 0 replies; 4+ messages in thread
From: Sasha Levin @ 2025-11-24 17:45 UTC (permalink / raw)
To: stable; +Cc: Darrick J. Wong, Christoph Hellwig, Carlos Maiolino, Sasha Levin
From: "Darrick J. Wong" <djwong@kernel.org>
[ Upstream commit 678e1cc2f482e0985a0613ab4a5bf89c497e5acc ]
xfs/286 produced this report on my test fleet:
==================================================================
BUG: KFENCE: out-of-bounds read in memcpy_orig+0x54/0x110
Out-of-bounds read at 0xffff88843fe9e038 (184B right of kfence-#184):
memcpy_orig+0x54/0x110
xrep_symlink_salvage_inline+0xb3/0xf0 [xfs]
xrep_symlink_salvage+0x100/0x110 [xfs]
xrep_symlink+0x2e/0x80 [xfs]
xrep_attempt+0x61/0x1f0 [xfs]
xfs_scrub_metadata+0x34f/0x5c0 [xfs]
xfs_ioc_scrubv_metadata+0x387/0x560 [xfs]
xfs_file_ioctl+0xe23/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
kfence-#184: 0xffff88843fe9df80-0xffff88843fe9dfea, size=107, cache=kmalloc-128
allocated by task 3470 on cpu 1 at 263329.131592s (192823.508886s ago):
xfs_init_local_fork+0x79/0xe0 [xfs]
xfs_iformat_local+0xa4/0x170 [xfs]
xfs_iformat_data_fork+0x148/0x180 [xfs]
xfs_inode_from_disk+0x2cd/0x480 [xfs]
xfs_iget+0x450/0xd60 [xfs]
xfs_bulkstat_one_int+0x6b/0x510 [xfs]
xfs_bulkstat_iwalk+0x1e/0x30 [xfs]
xfs_iwalk_ag_recs+0xdf/0x150 [xfs]
xfs_iwalk_run_callbacks+0xb9/0x190 [xfs]
xfs_iwalk_ag+0x1dc/0x2f0 [xfs]
xfs_iwalk_args.constprop.0+0x6a/0x120 [xfs]
xfs_iwalk+0xa4/0xd0 [xfs]
xfs_bulkstat+0xfa/0x170 [xfs]
xfs_ioc_fsbulkstat.isra.0+0x13a/0x230 [xfs]
xfs_file_ioctl+0xbf2/0x10e0 [xfs]
__x64_sys_ioctl+0x76/0xc0
do_syscall_64+0x4e/0x1e0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
CPU: 1 UID: 0 PID: 1300113 Comm: xfs_scrub Not tainted 6.18.0-rc4-djwx #rc4 PREEMPT(lazy) 3d744dd94e92690f00a04398d2bd8631dcef1954
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-4.module+el8.8.0+21164+ed375313 04/01/2014
==================================================================
On further analysis, I realized that the second parameter to min() is
not correct. xfs_ifork::if_bytes is the size of the xfs_ifork::if_data
buffer. if_bytes can be smaller than the data fork size because:
(a) the forkoff code tries to keep the data area as large as possible
(b) for symbolic links, if_bytes is the ondisk file size + 1
(c) forkoff is always a multiple of 8.
Case in point: for a single-byte symlink target, forkoff will be
8 but the buffer will only be 2 bytes long.
In other words, the logic here is wrong and we walk off the end of the
incore buffer. Fix that.
Cc: stable@vger.kernel.org # v6.10
Fixes: 2651923d8d8db0 ("xfs: online repair of symbolic links")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/xfs/scrub/symlink_repair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/xfs/scrub/symlink_repair.c b/fs/xfs/scrub/symlink_repair.c
index 5902398185a89..df629892462fe 100644
--- a/fs/xfs/scrub/symlink_repair.c
+++ b/fs/xfs/scrub/symlink_repair.c
@@ -184,7 +184,7 @@ xrep_symlink_salvage_inline(
sc->ip->i_disk_size == 1 && old_target[0] == '?')
return 0;
- nr = min(XFS_SYMLINK_MAXLEN, xfs_inode_data_fork_size(ip));
+ nr = min(XFS_SYMLINK_MAXLEN, ifp->if_bytes);
memcpy(target_buf, ifp->if_data, nr);
return nr;
}
--
2.51.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy
2025-11-24 17:45 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Sasha Levin
2025-11-24 17:45 ` [PATCH 6.17.y 2/2] xfs: fix out of bounds memory read error in symlink repair Sasha Levin
@ 2025-11-26 22:39 ` Darrick J. Wong
1 sibling, 0 replies; 4+ messages in thread
From: Darrick J. Wong @ 2025-11-26 22:39 UTC (permalink / raw)
To: Sasha Levin
Cc: stable, Marcelo Moreira, Dave Chinner, Christoph Hellwig,
Carlos Maiolino, Carlos Maiolino
On Mon, Nov 24, 2025 at 12:45:02PM -0500, Sasha Levin wrote:
> From: Marcelo Moreira <marcelomoreira1905@gmail.com>
>
> [ Upstream commit 33ddc796ecbd50cd6211aa9e9eddbf4567038b49 ]
>
> The changes modernizes the code by aligning it with current kernel best
> practices. It improves code clarity and consistency, as strncpy is deprecated
> as explained in Documentation/process/deprecated.rst. This change does
> not alter the functionality or introduce any behavioral changes.
>
> Suggested-by: Dave Chinner <david@fromorbit.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
> Signed-off-by: Marcelo Moreira <marcelomoreira1905@gmail.com>
> Reviewed-by: Darrick J. Wong <djwong@kernel.org>
> Signed-off-by: Carlos Maiolino <cem@kernel.org>
> Stable-dep-of: 678e1cc2f482 ("xfs: fix out of bounds memory read error in symlink repair")
> Signed-off-by: Sasha Levin <sashal@kernel.org>
The backports of patches 1-2 look good to me,
Acked-by: "Darrick J. Wong" <djwong@kernel.org>
--D
> ---
> fs/xfs/scrub/symlink_repair.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/xfs/scrub/symlink_repair.c b/fs/xfs/scrub/symlink_repair.c
> index 953ce7be78dc2..5902398185a89 100644
> --- a/fs/xfs/scrub/symlink_repair.c
> +++ b/fs/xfs/scrub/symlink_repair.c
> @@ -185,7 +185,7 @@ xrep_symlink_salvage_inline(
> return 0;
>
> nr = min(XFS_SYMLINK_MAXLEN, xfs_inode_data_fork_size(ip));
> - strncpy(target_buf, ifp->if_data, nr);
> + memcpy(target_buf, ifp->if_data, nr);
> return nr;
> }
>
> --
> 2.51.0
>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-11-24 13:25 FAILED: patch "[PATCH] xfs: fix out of bounds memory read error in symlink repair" failed to apply to 6.17-stable tree gregkh
2025-11-24 17:45 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Sasha Levin
2025-11-24 17:45 ` [PATCH 6.17.y 2/2] xfs: fix out of bounds memory read error in symlink repair Sasha Levin
2025-11-26 22:39 ` [PATCH 6.17.y 1/2] xfs: Replace strncpy with memcpy Darrick J. Wong
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