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CVE PROGRAM SOURCE RECORDUnscored

CVE-2025-71123

ext4: fix string copying in parse_apply_sb_mount_options()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix string copying in parse_apply_sb_mount_options() strscpy_pad() can't be used to copy a non-NUL-term string into a NUL-term string of possibly bigger size. Commit 0efc5990bca5 ("string.h: Introduce memtostr() and memtostr_pad()") provides additional information in that regard. So if this happens, the following warning is observed: strnlen: detected buffer overflow: 65 byte read of buffer size 64 WARNING: CPU: 0 PID: 28655 at lib/string_helpers.c:1032 __fortify_report+0x96/0xc0 lib/string_helpers.c:1032 Modules linked in: CPU: 0 UID: 0 PID: 28655 Comm: syz-executor.3 Not tainted 6.12.54-syzkaller-00144-g5f0270f1ba00 #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:__fortify_report+0x96/0xc0 lib/string_helpers.c:1032 Call Trace: <TASK> __fortify_panic+0x1f/0x30 lib/string_helpers.c:1039 strnlen include/linux/fortify-string.h:235 [inline] sized_strscpy include/linux/fortify-string.h:309 [inline] parse_apply_sb_mount_options fs/ext4/super.c:2504 [inline] __ext4_fill_super fs/ext4/super.c:5261 [inline] ext4_fill_super+0x3c35/0xad00 fs/ext4/super.c:5706 get_tree_bdev_flags+0x387/0x620 fs/super.c:1636 vfs_get_tree+0x93/0x380 fs/super.c:1814 do_new_mount fs/namespace.c:3553 [inline] path_mount+0x6ae/0x1f70 fs/namespace.c:3880 do_mount fs/namespace.c:3893 [inline] __do_sys_mount fs/namespace.c:4103 [inline] __se_sys_mount fs/namespace.c:4080 [inline] __x64_sys_mount+0x280/0x300 fs/namespace.c:4080 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x64/0x140 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x76/0x7e Since userspace is expected to provide s_mount_opts field to be at most 63 characters long with the ending byte being NUL-term, use a 64-byte buffer which matches the size of s_mount_opts, so that strscpy_pad() does its job properly. Return with error if the user still managed to provide a non-NUL-term string here. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • b2bac84fde28fb6a88817b8b761abda17a1d300b to < 52ac96c4a2dd7bc47666000440b0602d9742e820affected
  • e651294218d2684302ee5ed95ccf381646f3e5b4 to < 6e37143560e37869d51b7d9e0ac61fc48895f8a0affected
  • 01829af7656b56d83682b3491265d583d502e502 to < 902ca2356f1e3ec5355c5808ad5d3f9d0095b0ccaffected
  • 2a0cf438320cdb783e0378570744c0ef0d83e934 to < db9ee13fab0267eccf6544ee35b16c9522db9aacaffected
  • 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 to < 5bbacbbf1ca4419861dca3c6b82707c10e9c021caffected
  • 8ecb790ea8c3fc69e77bace57f14cf0d7c177bd8 to < ee5a977b4e771cc181f39d504426dbd31ed701ccaffected
  • 7bf46ff83a0ef11836e38ebd72cdc5107209342daffected
  • a6e94557cd05adc82fae0400f6e17745563e5412affected
  • 5.10.246 to < 5.10.248affected
  • 6.1.158 to < 6.1.160affected
  • 6.6.114 to < 6.6.120affected
  • 6.12.54 to < 6.12.64affected
  • 5.4.301 to < 5.5affected
  • 6.17.4 to < 6.18affected

Linux Linux

Default version status: affected

  • 6.18affected
  • 0 to < 6.18unaffected
  • 5.10.248 to ≤ 5.10.*unaffected
  • 6.1.160 to ≤ 6.1.*unaffected
  • 6.6.120 to ≤ 6.6.*unaffected
  • 6.12.64 to ≤ 6.12.*unaffected
  • 6.18.3 to ≤ 6.18.*unaffected
  • 6.19 to ≤ *unaffected

References