{ "containers": { "cna": { "providerMetadata": { "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: fix a NULL pointer dereference when failed to start a new trasacntion\n\n[BUG]\nSyzbot reported a NULL pointer dereference with the following crash:\n\n FAULT_INJECTION: forcing a failure.\n start_transaction+0x830/0x1670 fs/btrfs/transaction.c:676\n prepare_to_relocate+0x31f/0x4c0 fs/btrfs/relocation.c:3642\n relocate_block_group+0x169/0xd20 fs/btrfs/relocation.c:3678\n ...\n BTRFS info (device loop0): balance: ended with status: -12\n Oops: general protection fault, probably for non-canonical address 0xdffffc00000000cc: 0000 [#1] PREEMPT SMP KASAN NOPTI\n KASAN: null-ptr-deref in range [0x0000000000000660-0x0000000000000667]\n RIP: 0010:btrfs_update_reloc_root+0x362/0xa80 fs/btrfs/relocation.c:926\n Call Trace:\n \n commit_fs_roots+0x2ee/0x720 fs/btrfs/transaction.c:1496\n btrfs_commit_transaction+0xfaf/0x3740 fs/btrfs/transaction.c:2430\n del_balance_item fs/btrfs/volumes.c:3678 [inline]\n reset_balance_state+0x25e/0x3c0 fs/btrfs/volumes.c:3742\n btrfs_balance+0xead/0x10c0 fs/btrfs/volumes.c:4574\n btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:907 [inline]\n __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893\n do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n[CAUSE]\nThe allocation failure happens at the start_transaction() inside\nprepare_to_relocate(), and during the error handling we call\nunset_reloc_control(), which makes fs_info->balance_ctl to be NULL.\n\nThen we continue the error path cleanup in btrfs_balance() by calling\nreset_balance_state() which will call del_balance_item() to fully delete\nthe balance item in the root tree.\n\nHowever during the small window between set_reloc_contrl() and\nunset_reloc_control(), we can have a subvolume tree update and created a\nreloc_root for that subvolume.\n\nThen we go into the final btrfs_commit_transaction() of\ndel_balance_item(), and into btrfs_update_reloc_root() inside\ncommit_fs_roots().\n\nThat function checks if fs_info->reloc_ctl is in the merge_reloc_tree\nstage, but since fs_info->reloc_ctl is NULL, it results a NULL pointer\ndereference.\n\n[FIX]\nJust add extra check on fs_info->reloc_ctl inside\nbtrfs_update_reloc_root(), before checking\nfs_info->reloc_ctl->merge_reloc_tree.\n\nThat DEAD_RELOC_TREE handling is to prevent further modification to the\nreloc tree during merge stage, but since there is no reloc_ctl at all,\nwe do not need to bother that." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/btrfs/relocation.c" ], "versions": [ { "version": "1da177e4c3f4", "lessThan": "d73d48acf36f", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f4", "lessThan": "37fee9c220b9", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f4", "lessThan": "d13249c0df7a", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f4", "lessThan": "7ad0c5868f2f", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f4", "lessThan": "dc02c1440705", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f4", "lessThan": "39356ec0e319", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f4", "lessThan": "c3b47f49e831", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "fs/btrfs/relocation.c" ], "versions": [ { "version": "5.10.227", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.15.168", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.1.113", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.6.55", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.10.14", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.11.3", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.12-rc2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/d73d48acf36f57362df7e4f9d76568168bf5e944" }, { "url": "https://git.kernel.org/stable/c/37fee9c220b92c3b7bf22b51c51dde5364e7590b" }, { "url": "https://git.kernel.org/stable/c/d13249c0df7aab885acb149695f82c54c0822a70" }, { "url": "https://git.kernel.org/stable/c/7ad0c5868f2f0418619089513d95230c66cb7eb4" }, { "url": "https://git.kernel.org/stable/c/dc02c1440705e3451abd1c2c8114a5c1bb188e9f" }, { "url": "https://git.kernel.org/stable/c/39356ec0e319ed07627b3a0f402d0608546509e6" }, { "url": "https://git.kernel.org/stable/c/c3b47f49e83197e8dffd023ec568403bcdbb774b" } ], "title": "btrfs: fix a NULL pointer dereference when failed to start a new trasacntion", "x_generator": { "engine": "bippy-c9c4e1df01b2" } } }, "cveMetadata": { "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038", "cveID": "CVE-2024-49868", "requesterUserId": "gregkh@kernel.org", "serial": "1", "state": "PUBLISHED" }, "dataType": "CVE_RECORD", "dataVersion": "5.0" }