{"id":"CVE-2024-49869","summary":"btrfs: send: fix buffer overflow detection when copying path to cache entry","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: send: fix buffer overflow detection when copying path to cache entry\n\nStarting with commit c0247d289e73 (\"btrfs: send: annotate struct\nname_cache_entry with __counted_by()\") we annotated the variable length\narray \"name\" from the name_cache_entry structure with __counted_by() to\nimprove overflow detection. However that alone was not correct, because\nthe length of that array does not match the \"name_len\" field - it matches\nthat plus 1 to include the NUL string terminator, so that makes a\nfortified kernel think there's an overflow and report a splat like this:\n\n  strcpy: detected buffer overflow: 20 byte write of buffer size 19\n  WARNING: CPU: 3 PID: 3310 at __fortify_report+0x45/0x50\n  CPU: 3 UID: 0 PID: 3310 Comm: btrfs Not tainted 6.11.0-prnet #1\n  Hardware name: CompuLab Ltd.  sbc-ihsw/Intense-PC2 (IPC2), BIOS IPC2_3.330.7 X64 03/15/2018\n  RIP: 0010:__fortify_report+0x45/0x50\n  Code: 48 8b 34 (...)\n  RSP: 0018:ffff97ebc0d6f650 EFLAGS: 00010246\n  RAX: 7749924ef60fa600 RBX: ffff8bf5446a521a RCX: 0000000000000027\n  RDX: 00000000ffffdfff RSI: ffff97ebc0d6f548 RDI: ffff8bf84e7a1cc8\n  RBP: ffff8bf548574080 R08: ffffffffa8c40e10 R09: 0000000000005ffd\n  R10: 0000000000000004 R11: ffffffffa8c70e10 R12: ffff8bf551eef400\n  R13: 0000000000000000 R14: 0000000000000013 R15: 00000000000003a8\n  FS:  00007fae144de8c0(0000) GS:ffff8bf84e780000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007fae14691690 CR3: 00000001027a2003 CR4: 00000000001706f0\n  Call Trace:\n   \u003cTASK\u003e\n   ? __warn+0x12a/0x1d0\n   ? __fortify_report+0x45/0x50\n   ? report_bug+0x154/0x1c0\n   ? handle_bug+0x42/0x70\n   ? exc_invalid_op+0x1a/0x50\n   ? asm_exc_invalid_op+0x1a/0x20\n   ? __fortify_report+0x45/0x50\n   __fortify_panic+0x9/0x10\n  __get_cur_name_and_parent+0x3bc/0x3c0\n   get_cur_path+0x207/0x3b0\n   send_extent_data+0x709/0x10d0\n   ? find_parent_nodes+0x22df/0x25d0\n   ? mas_nomem+0x13/0x90\n   ? mtree_insert_range+0xa5/0x110\n   ? btrfs_lru_cache_store+0x5f/0x1e0\n   ? iterate_extent_inodes+0x52d/0x5a0\n   process_extent+0xa96/0x11a0\n   ? __pfx_lookup_backref_cache+0x10/0x10\n   ? __pfx_store_backref_cache+0x10/0x10\n   ? __pfx_iterate_backrefs+0x10/0x10\n   ? __pfx_check_extent_item+0x10/0x10\n   changed_cb+0x6fa/0x930\n   ? tree_advance+0x362/0x390\n   ? memcmp_extent_buffer+0xd7/0x160\n   send_subvol+0xf0a/0x1520\n   btrfs_ioctl_send+0x106b/0x11d0\n   ? __pfx___clone_root_cmp_sort+0x10/0x10\n   _btrfs_ioctl_send+0x1ac/0x240\n   btrfs_ioctl+0x75b/0x850\n   __se_sys_ioctl+0xca/0x150\n   do_syscall_64+0x85/0x160\n   ? __count_memcg_events+0x69/0x100\n   ? handle_mm_fault+0x1327/0x15c0\n   ? __se_sys_rt_sigprocmask+0xf1/0x180\n   ? syscall_exit_to_user_mode+0x75/0xa0\n   ? do_syscall_64+0x91/0x160\n   ? do_user_addr_fault+0x21d/0x630\n  entry_SYSCALL_64_after_hwframe+0x76/0x7e\n  RIP: 0033:0x7fae145eeb4f\n  Code: 00 48 89 (...)\n  RSP: 002b:00007ffdf1cb09b0 EFLAGS: 00000246 ORIG_RAX: 0000000000000010\n  RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fae145eeb4f\n  RDX: 00007ffdf1cb0ad0 RSI: 0000000040489426 RDI: 0000000000000004\n  RBP: 00000000000078fe R08: 00007fae144006c0 R09: 00007ffdf1cb0927\n  R10: 0000000000000008 R11: 0000000000000246 R12: 00007ffdf1cb1ce8\n  R13: 0000000000000003 R14: 000055c499fab2e0 R15: 0000000000000004\n   \u003c/TASK\u003e\n\nFix this by not storing the NUL string terminator since we don't actually\nneed it for name cache entries, this way \"name_len\" corresponds to the\nactual size of the \"name\" array. This requires marking the \"name\" array\nfield with __nonstring and using memcpy() instead of strcpy() as\nrecommended by the guidelines at:\n\n   https://github.com/KSPP/linux/issues/90","modified":"2026-04-02T12:21:03.916941Z","published":"2024-10-21T18:01:11.389Z","related":["USN-7276-1","USN-7277-1","openSUSE-SU-2024:14500-1","openSUSE-SU-2025:14705-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/49xxx/CVE-2024-49869.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/843738ede6cb8b959fb22591fcbabe8b456d7216"},{"type":"WEB","url":"https://git.kernel.org/stable/c/96c6ca71572a3556ed0c37237305657ff47174b7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/49xxx/CVE-2024-49869.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-49869"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c0247d289e73e18f6ddb0895de30c09770fbed95"},{"fixed":"843738ede6cb8b959fb22591fcbabe8b456d7216"},{"fixed":"96c6ca71572a3556ed0c37237305657ff47174b7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-49869.json"}}],"schema_version":"1.7.5"}