FAILED: patch "[PATCH] Squashfs: reject negative file sizes in squashfs_read_inode()" failed to apply to 6.12-stable tree

PATCH New [email protected] 2 participants 3 messages Oct 13, 2025

Subsystems (2)

Stable branch SquashFS file system

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[email protected]

author maintainer

2025-10-13 07:49 UTC #0 lore raw

The patch below does not apply to the 6.12-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 <[email protected]>.

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-6.12.y
git checkout FETCH_HEAD
git cherry-pick -x 9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2025101320-sliceable-electable-e1b9@gregkh' --subject-prefix 'PATCH 6.12.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b Mon Sep 17 00:00:00 2001
From: Phillip Lougher <[email protected]>
Date: Fri, 26 Sep 2025 22:59:35 +0100
Subject: [PATCH] Squashfs: reject negative file sizes in squashfs_read_inode()

Syskaller reports a "WARNING in ovl_copy_up_file" in overlayfs.

This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size.

This commit checks for a negative file size and returns EINVAL.

[[email protected]: only need to check 64 bit quantity]

Link https://lkml.kernel.org/r/[email protected] open here

Fixes 6545b246a2c8 ("Squashfs: inode operations")

Signed-off-by Phillip Lougher <[email protected]>

Reported-by [email protected]

Closes https://lore.kernel.org/all/[email protected]/ open here

Cc Amir Goldstein <[email protected]>

Cc <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

fs/squashfs/inode.c +4 -0

index ddc65d006063..cceae3b78698 100644
@@ -197,6 +197,10 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 			goto failed_read;
 
 		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
+		if (inode->i_size < 0) {
+			err = -EINVAL;
+			goto failed_read;
+		}
 		frag = le32_to_cpu(sqsh_ino->fragment);
 		if (frag != SQUASHFS_INVALID_FRAG) {
 			/*

Sasha Levin

maintainer

2025-10-13 19:28 UTC #1 lore raw

PATCH 1/2 Squashfs: add additional inode sanity checking

From: Phillip Lougher <[email protected]>

[ Upstream commit 9ee94bfbe930a1b39df53fa2d7b31141b780eb5a ]

Patch series "Squashfs: performance improvement and a sanity check".

This patchset adds an additional sanity check when reading regular file inodes, and adds support for SEEK_DATA/SEEK_HOLE lseek() whence values.

This patch (of 2):

Add an additional sanity check when reading regular file inodes.

A regular file if the file size is an exact multiple of the filesystem block size cannot have a fragment. This is because by definition a fragment block stores tailends which are not a whole block in size.

Link https://lkml.kernel.org/r/[email protected] open here

Signed-off-by Phillip Lougher <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

Stable-dep-of: 9f1c14c1de1b ("Squashfs: reject negative file sizes in squashfs_read_inode()")

Signed-off-by Sasha Levin <[email protected]>

---
 fs/squashfs/inode.c | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

fs/squashfs/inode.c +18 -2

index d5918eba27e37..77eec1772998b 100644
@@ -140,8 +140,17 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 		if (err < 0)
 			goto failed_read;
 
+		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 		frag = le32_to_cpu(sqsh_ino->fragment);
 		if (frag != SQUASHFS_INVALID_FRAG) {
+			/*
+			 * the file cannot have a fragment (tailend) and have a
+			 * file size a multiple of the block size
+			 */
+			if ((inode->i_size & (msblk->block_size - 1)) == 0) {
+				err = -EINVAL;
+				goto failed_read;
+			}
 			frag_offset = le32_to_cpu(sqsh_ino->offset);
 			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 			if (frag_size < 0) {

@@ -155,7 +164,6 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 		}
 
 		set_nlink(inode, 1);
-		inode->i_size = le32_to_cpu(sqsh_ino->file_size);
 		inode->i_fop = &generic_ro_fops;
 		inode->i_mode |= S_IFREG;
 		inode->i_blocks = ((inode->i_size - 1) >> 9) + 1;

@@ -183,8 +191,17 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 		if (err < 0)
 			goto failed_read;
 
+		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
 		frag = le32_to_cpu(sqsh_ino->fragment);
 		if (frag != SQUASHFS_INVALID_FRAG) {
+			/*
+			 * the file cannot have a fragment (tailend) and have a
+			 * file size a multiple of the block size
+			 */
+			if ((inode->i_size & (msblk->block_size - 1)) == 0) {
+				err = -EINVAL;
+				goto failed_read;
+			}
 			frag_offset = le32_to_cpu(sqsh_ino->offset);
 			frag_size = squashfs_frag_lookup(sb, frag, &frag_blk);
 			if (frag_size < 0) {

@@ -199,7 +216,6 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 
 		xattr_id = le32_to_cpu(sqsh_ino->xattr);
 		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
-		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
 		inode->i_op = &squashfs_inode_ops;
 		inode->i_fop = &generic_ro_fops;
 		inode->i_mode |= S_IFREG;

Signature · 1 line

2.51.0

Sasha Levin

maintainer

2025-10-13 19:28 UTC #2 lore raw

PATCH 2/2 Squashfs: reject negative file sizes in squashfs_read_inode()

From: Phillip Lougher <[email protected]>

[ Upstream commit 9f1c14c1de1bdde395f6cc893efa4f80a2ae3b2b ]

Syskaller reports a "WARNING in ovl_copy_up_file" in overlayfs.

This warning is ultimately caused because the underlying Squashfs file system returns a file with a negative file size.

This commit checks for a negative file size and returns EINVAL.

[[email protected]: only need to check 64 bit quantity]

Link https://lkml.kernel.org/r/[email protected] open here

Fixes 6545b246a2c8 ("Squashfs: inode operations")

Signed-off-by Phillip Lougher <[email protected]>

Reported-by [email protected]

Closes https://lore.kernel.org/all/[email protected]/ open here

Cc Amir Goldstein <[email protected]>

Cc <[email protected]>

Signed-off-by Andrew Morton <[email protected]>

Signed-off-by Sasha Levin <[email protected]>

---
 fs/squashfs/inode.c | 4 ++++
 1 file changed, 4 insertions(+)

fs/squashfs/inode.c +4 -0

index 77eec1772998b..de8657a77703a 100644
@@ -192,6 +192,10 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 			goto failed_read;
 
 		inode->i_size = le64_to_cpu(sqsh_ino->file_size);
+		if (inode->i_size < 0) {
+			err = -EINVAL;
+			goto failed_read;
+		}
 		frag = le32_to_cpu(sqsh_ino->fragment);
 		if (frag != SQUASHFS_INVALID_FRAG) {
 			/*

Signature · 1 line

2.51.0