Message ID | 20220812141329.9501-1-lhenriques@suse.de |
---|---|
State | Superseded |
Headers | show |
Series | [v3] ext4: fix bug in extents parsing when eh_entries == 0 and eh_depth > 0 | expand |
Hi "Luís, Thank you for the patch! Yet something to improve: [auto build test ERROR on tytso-ext4/dev] [also build test ERROR on linus/master v5.19 next-20220812] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch#_base_tree_information] url: https://github.com/intel-lab-lkp/linux/commits/Lu-s-Henriques/ext4-fix-bug-in-extents-parsing-when-eh_entries-0-and-eh_depth-0/20220812-221443 base: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev config: arm64-buildonly-randconfig-r002-20220812 (https://download.01.org/0day-ci/archive/20220813/202208130421.BZpzWWRK-lkp@intel.com/config) compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 5f1c7e2cc5a3c07cbc2412e851a7283c1841f520) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm64 cross compiling tool for clang build # apt-get install binutils-aarch64-linux-gnu # https://github.com/intel-lab-lkp/linux/commit/ef3617646de6e939d29961099c7c8adcaa0d9fd9 git remote add linux-review https://github.com/intel-lab-lkp/linux git fetch --no-tags linux-review Lu-s-Henriques/ext4-fix-bug-in-extents-parsing-when-eh_entries-0-and-eh_depth-0/20220812-221443 git checkout ef3617646de6e939d29961099c7c8adcaa0d9fd9 # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=arm64 SHELL=/bin/bash fs/ext4/ If you fix the issue, kindly add following tag where applicable Reported-by: kernel test robot <lkp@intel.com> All errors (new ones prefixed by >>): >> fs/ext4/extents.c:463:41: error: use of undeclared identifier 'eh_depth'; did you mean 'ext_depth'? if (unlikely((eh->eh_entries == 0) && (eh_depth > 0))) { ^~~~~~~~ ext_depth include/linux/compiler.h:78:42: note: expanded from macro 'unlikely' # define unlikely(x) __builtin_expect(!!(x), 0) ^ fs/ext4/ext4_extents.h:192:30: note: 'ext_depth' declared here static inline unsigned short ext_depth(struct inode *inode) ^ 1 error generated. vim +463 fs/ext4/extents.c 434 435 static int __ext4_ext_check(const char *function, unsigned int line, 436 struct inode *inode, struct ext4_extent_header *eh, 437 int depth, ext4_fsblk_t pblk, ext4_lblk_t lblk) 438 { 439 const char *error_msg; 440 int max = 0, err = -EFSCORRUPTED; 441 442 if (unlikely(eh->eh_magic != EXT4_EXT_MAGIC)) { 443 error_msg = "invalid magic"; 444 goto corrupted; 445 } 446 if (unlikely(le16_to_cpu(eh->eh_depth) != depth)) { 447 error_msg = "unexpected eh_depth"; 448 goto corrupted; 449 } 450 if (unlikely(eh->eh_max == 0)) { 451 error_msg = "invalid eh_max"; 452 goto corrupted; 453 } 454 max = ext4_ext_max_entries(inode, depth); 455 if (unlikely(le16_to_cpu(eh->eh_max) > max)) { 456 error_msg = "too large eh_max"; 457 goto corrupted; 458 } 459 if (unlikely(le16_to_cpu(eh->eh_entries) > le16_to_cpu(eh->eh_max))) { 460 error_msg = "invalid eh_entries"; 461 goto corrupted; 462 } > 463 if (unlikely((eh->eh_entries == 0) && (eh_depth > 0))) { 464 error_msg = "eh_entries is 0 but eh_depth is > 0"; 465 goto corrupted; 466 } 467 if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) { 468 error_msg = "invalid extent entries"; 469 goto corrupted; 470 } 471 if (unlikely(depth > 32)) { 472 error_msg = "too large eh_depth"; 473 goto corrupted; 474 } 475 /* Verify checksum on non-root extent tree nodes */ 476 if (ext_depth(inode) != depth && 477 !ext4_extent_block_csum_verify(inode, eh)) { 478 error_msg = "extent tree corrupted"; 479 err = -EFSBADCRC; 480 goto corrupted; 481 } 482 return 0; 483 484 corrupted: 485 ext4_error_inode_err(inode, function, line, 0, -err, 486 "pblk %llu bad header/extent: %s - magic %x, " 487 "entries %u, max %u(%u), depth %u(%u)", 488 (unsigned long long) pblk, error_msg, 489 le16_to_cpu(eh->eh_magic), 490 le16_to_cpu(eh->eh_entries), 491 le16_to_cpu(eh->eh_max), 492 max, le16_to_cpu(eh->eh_depth), depth); 493 return err; 494 } 495
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index c148bb97b527..2654fe46a1ea 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -460,6 +460,10 @@ static int __ext4_ext_check(const char *function, unsigned int line, error_msg = "invalid eh_entries"; goto corrupted; } + if (unlikely((eh->eh_entries == 0) && (eh_depth > 0))) { + error_msg = "eh_entries is 0 but eh_depth is > 0"; + goto corrupted; + } if (!ext4_valid_extent_entries(inode, eh, lblk, &pblk, depth)) { error_msg = "invalid extent entries"; goto corrupted;
When walking through an inode extents, the ext4_ext_binsearch_idx() function assumes that the extent header has been previously validated. However, there are no checks that verify that the number of entries (eh->eh_entries) is non-zero when depth is > 0. And this will lead to problems because the EXT_FIRST_INDEX() and EXT_LAST_INDEX() will return garbage and result in this: [ 135.245946] ------------[ cut here ]------------ [ 135.247579] kernel BUG at fs/ext4/extents.c:2258! [ 135.249045] invalid opcode: 0000 [#1] PREEMPT SMP [ 135.250320] CPU: 2 PID: 238 Comm: tmp118 Not tainted 5.19.0-rc8+ #4 [ 135.252067] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.15.0-0-g2dd4b9b-rebuilt.opensuse.org 04/01/2014 [ 135.255065] RIP: 0010:ext4_ext_map_blocks+0xc20/0xcb0 [ 135.256475] Code: [ 135.261433] RSP: 0018:ffffc900005939f8 EFLAGS: 00010246 [ 135.262847] RAX: 0000000000000024 RBX: ffffc90000593b70 RCX: 0000000000000023 [ 135.264765] RDX: ffff8880038e5f10 RSI: 0000000000000003 RDI: ffff8880046e922c [ 135.266670] RBP: ffff8880046e9348 R08: 0000000000000001 R09: ffff888002ca580c [ 135.268576] R10: 0000000000002602 R11: 0000000000000000 R12: 0000000000000024 [ 135.270477] R13: 0000000000000000 R14: 0000000000000024 R15: 0000000000000000 [ 135.272394] FS: 00007fdabdc56740(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 [ 135.274510] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 135.276075] CR2: 00007ffc26bd4f00 CR3: 0000000006261004 CR4: 0000000000170ea0 [ 135.277952] Call Trace: [ 135.278635] <TASK> [ 135.279247] ? preempt_count_add+0x6d/0xa0 [ 135.280358] ? percpu_counter_add_batch+0x55/0xb0 [ 135.281612] ? _raw_read_unlock+0x18/0x30 [ 135.282704] ext4_map_blocks+0x294/0x5a0 [ 135.283745] ? xa_load+0x6f/0xa0 [ 135.284562] ext4_mpage_readpages+0x3d6/0x770 [ 135.285646] read_pages+0x67/0x1d0 [ 135.286492] ? folio_add_lru+0x51/0x80 [ 135.287441] page_cache_ra_unbounded+0x124/0x170 [ 135.288510] filemap_get_pages+0x23d/0x5a0 [ 135.289457] ? path_openat+0xa72/0xdd0 [ 135.290332] filemap_read+0xbf/0x300 [ 135.291158] ? _raw_spin_lock_irqsave+0x17/0x40 [ 135.292192] new_sync_read+0x103/0x170 [ 135.293014] vfs_read+0x15d/0x180 [ 135.293745] ksys_read+0xa1/0xe0 [ 135.294461] do_syscall_64+0x3c/0x80 [ 135.295284] entry_SYSCALL_64_after_hwframe+0x46/0xb0 This patch simply adds an extra check in __ext4_ext_check(), verifying that eh_entries is not 0 when eh_depth is > 0. Link: https://bugzilla.kernel.org/show_bug.cgi?id=215941 Link: https://bugzilla.kernel.org/show_bug.cgi?id=216283 Cc: Baokun Li <libaokun1@huawei.com> Signed-off-by: Luís Henriques <lhenriques@suse.de> --- fs/ext4/extents.c | 4 ++++ 1 file changed, 4 insertions(+) Changes since v2: - Dropped usage of le16_to_cpu() because we're comparing values against 0 - Use 'depth' instead of 'eh->eh_depth' because we've checked earlier that both have the same value.