[PATCH openEuler-1.0-LTS 0/2] Fix CVE-2025-37785
Fix CVE-2025-37785. Acs, Jakub (1): ext4: fix OOB read when checking dotdot dir Theodore Ts'o (1): ext4: optimize __ext4_check_dir_entry() fs/ext4/dir.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) -- 2.39.2
From: Theodore Ts'o <tytso@mit.edu> mainline inclusion from mainline-v5.5-rc3 commit 707d1a2f601bea6110a5633054253c0cb71b44c1 category: cleanup bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC2CCG CVE: CVE-2025-37785 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- Make __ext4_check_dir_entry() a bit easier to understand, and reduce the object size of the function by over 11%. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Link: https://lore.kernel.org/r/20191209004346.38526-1-tytso@mit.edu Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/ext4/dir.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index aed33af7551e..b1c649152364 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -68,6 +68,7 @@ int __ext4_check_dir_entry(const char *function, unsigned int line, const char *error_msg = NULL; const int rlen = ext4_rec_len_from_disk(de->rec_len, dir->i_sb->s_blocksize); + const int next_offset = ((char *) de - buf) + rlen; if (unlikely(rlen < EXT4_DIR_REC_LEN(1))) error_msg = "rec_len is smaller than minimal"; @@ -75,13 +76,11 @@ int __ext4_check_dir_entry(const char *function, unsigned int line, error_msg = "rec_len % 4 != 0"; else if (unlikely(rlen < EXT4_DIR_REC_LEN(de->name_len))) error_msg = "rec_len is too small for name_len"; - else if (unlikely(((char *) de - buf) + rlen > size)) + else if (unlikely(next_offset > size)) error_msg = "directory entry overrun"; - else if (unlikely(((char *) de - buf) + rlen > - size - EXT4_DIR_REC_LEN(1) && - ((char *) de - buf) + rlen != size)) { + else if (unlikely(next_offset > size - EXT4_DIR_REC_LEN(1) && + next_offset != size)) error_msg = "directory entry too close to block end"; - } else if (unlikely(le32_to_cpu(de->inode) > le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))) error_msg = "inode out of bounds"; -- 2.39.2
From: "Acs, Jakub" <acsjakub@amazon.de> stable inclusion from stable-v5.10.236 commit e47f472a664d70a3d104a6c2a035cdff55a719b4 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IC2CCG CVE: CVE-2025-37785 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit d5e206778e96e8667d3bde695ad372c296dc9353 upstream. Mounting a corrupted filesystem with directory which contains '.' dir entry with rec_len == block size results in out-of-bounds read (later on, when the corrupted directory is removed). ext4_empty_dir() assumes every ext4 directory contains at least '.' and '..' as directory entries in the first data block. It first loads the '.' dir entry, performs sanity checks by calling ext4_check_dir_entry() and then uses its rec_len member to compute the location of '..' dir entry (in ext4_next_entry). It assumes the '..' dir entry fits into the same data block. If the rec_len of '.' is precisely one block (4KB), it slips through the sanity checks (it is considered the last directory entry in the data block) and leaves "struct ext4_dir_entry_2 *de" point exactly past the memory slot allocated to the data block. The following call to ext4_check_dir_entry() on new value of de then dereferences this pointer which results in out-of-bounds mem access. Fix this by extending __ext4_check_dir_entry() to check for '.' dir entries that reach the end of data block. Make sure to ignore the phony dir entries for checksum (by checking name_len for non-zero). Note: This is reported by KASAN as use-after-free in case another structure was recently freed from the slot past the bound, but it is really an OOB read. This issue was found by syzkaller tool. Call Trace: [ 38.594108] BUG: KASAN: slab-use-after-free in __ext4_check_dir_entry+0x67e/0x710 [ 38.594649] Read of size 2 at addr ffff88802b41a004 by task syz-executor/5375 [ 38.595158] [ 38.595288] CPU: 0 UID: 0 PID: 5375 Comm: syz-executor Not tainted 6.14.0-rc7 #1 [ 38.595298] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 38.595304] Call Trace: [ 38.595308] <TASK> [ 38.595311] dump_stack_lvl+0xa7/0xd0 [ 38.595325] print_address_description.constprop.0+0x2c/0x3f0 [ 38.595339] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595349] print_report+0xaa/0x250 [ 38.595359] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595368] ? kasan_addr_to_slab+0x9/0x90 [ 38.595378] kasan_report+0xab/0xe0 [ 38.595389] ? __ext4_check_dir_entry+0x67e/0x710 [ 38.595400] __ext4_check_dir_entry+0x67e/0x710 [ 38.595410] ext4_empty_dir+0x465/0x990 [ 38.595421] ? __pfx_ext4_empty_dir+0x10/0x10 [ 38.595432] ext4_rmdir.part.0+0x29a/0xd10 [ 38.595441] ? __dquot_initialize+0x2a7/0xbf0 [ 38.595455] ? __pfx_ext4_rmdir.part.0+0x10/0x10 [ 38.595464] ? __pfx___dquot_initialize+0x10/0x10 [ 38.595478] ? down_write+0xdb/0x140 [ 38.595487] ? __pfx_down_write+0x10/0x10 [ 38.595497] ext4_rmdir+0xee/0x140 [ 38.595506] vfs_rmdir+0x209/0x670 [ 38.595517] ? lookup_one_qstr_excl+0x3b/0x190 [ 38.595529] do_rmdir+0x363/0x3c0 [ 38.595537] ? __pfx_do_rmdir+0x10/0x10 [ 38.595544] ? strncpy_from_user+0x1ff/0x2e0 [ 38.595561] __x64_sys_unlinkat+0xf0/0x130 [ 38.595570] do_syscall_64+0x5b/0x180 [ 38.595583] entry_SYSCALL_64_after_hwframe+0x76/0x7e Fixes: ac27a0ec112a0 ("[PATCH] ext4: initial copy of files from ext3") Signed-off-by: Jakub Acs <acsjakub@amazon.de> Cc: Theodore Ts'o <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: linux-ext4@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Mahmoud Adam <mngyadam@amazon.com> Cc: stable@vger.kernel.org Cc: security@kernel.org Link: https://patch.msgid.link/b3ae36a6794c4a01944c7d70b403db5b@amazon.de Signed-off-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Zizhi Wo <wozizhi@huawei.com> --- fs/ext4/dir.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c index b1c649152364..5def57966807 100644 --- a/fs/ext4/dir.c +++ b/fs/ext4/dir.c @@ -84,6 +84,9 @@ int __ext4_check_dir_entry(const char *function, unsigned int line, else if (unlikely(le32_to_cpu(de->inode) > le32_to_cpu(EXT4_SB(dir->i_sb)->s_es->s_inodes_count))) error_msg = "inode out of bounds"; + else if (unlikely(next_offset == size && de->name_len == 1 && + de->name[0] == '.')) + error_msg = "'.' directory cannot be the last in data block"; else return 0; -- 2.39.2
反馈： 您发送到kernel@openeuler.org的补丁/补丁集，已成功转换为PR！ PR链接地址： https://gitee.com/openeuler/kernel/pulls/15993 邮件列表地址：https://mailweb.openeuler.org/archives/list/kernel@openeuler.org/message/64Z... FeedBack: The patch(es) which you have sent to kernel@openeuler.org mailing list has been converted to a pull request successfully! Pull request link: https://gitee.com/openeuler/kernel/pulls/15993 Mailing list address: https://mailweb.openeuler.org/archives/list/kernel@openeuler.org/message/64Z...
participants (2)
-
patchwork bot -
Zizhi Wo