6.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Kang Chen k.chen@smail.nju.edu.cn
[ Upstream commit bea3e1d4467bcf292c8e54f080353d556d355e26 ]
BUG: KASAN: slab-out-of-bounds in hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186 Read of size 2 at addr ffff8880289ef218 by task syz.6.248/14290
CPU: 0 UID: 0 PID: 14290 Comm: syz.6.248 Not tainted 6.16.4 #1 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xca/0x5f0 mm/kasan/report.c:482 kasan_report+0xca/0x100 mm/kasan/report.c:595 hfsplus_uni2asc+0xa71/0xb90 fs/hfsplus/unicode.c:186 hfsplus_listxattr+0x5b6/0xbd0 fs/hfsplus/xattr.c:738 vfs_listxattr+0xbe/0x140 fs/xattr.c:493 listxattr+0xee/0x190 fs/xattr.c:924 filename_listxattr fs/xattr.c:958 [inline] path_listxattrat+0x143/0x360 fs/xattr.c:988 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe0e9fae16d Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fe0eae67f98 EFLAGS: 00000246 ORIG_RAX: 00000000000000c3 RAX: ffffffffffffffda RBX: 00007fe0ea205fa0 RCX: 00007fe0e9fae16d RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000200000000000 RBP: 00007fe0ea0480f0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe0ea206038 R14: 00007fe0ea205fa0 R15: 00007fe0eae48000 </TASK>
Allocated by task 14290: kasan_save_stack+0x24/0x50 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4333 [inline] __kmalloc_noprof+0x219/0x540 mm/slub.c:4345 kmalloc_noprof include/linux/slab.h:909 [inline] hfsplus_find_init+0x95/0x1f0 fs/hfsplus/bfind.c:21 hfsplus_listxattr+0x331/0xbd0 fs/hfsplus/xattr.c:697 vfs_listxattr+0xbe/0x140 fs/xattr.c:493 listxattr+0xee/0x190 fs/xattr.c:924 filename_listxattr fs/xattr.c:958 [inline] path_listxattrat+0x143/0x360 fs/xattr.c:988 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcb/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f
When hfsplus_uni2asc is called from hfsplus_listxattr, it actually passes in a struct hfsplus_attr_unistr*. The size of the corresponding structure is different from that of hfsplus_unistr, so the previous fix (94458781aee6) is insufficient. The pointer on the unicode buffer is still going beyond the allocated memory.
This patch introduces two warpper functions hfsplus_uni2asc_xattr_str and hfsplus_uni2asc_str to process two unicode buffers, struct hfsplus_attr_unistr* and struct hfsplus_unistr* respectively. When ustrlen value is bigger than the allocated memory size, the ustrlen value is limited to an safe size.
Fixes: 94458781aee6 ("hfsplus: fix slab-out-of-bounds read in hfsplus_uni2asc()") Signed-off-by: Kang Chen k.chen@smail.nju.edu.cn Reviewed-by: Viacheslav Dubeyko slava@dubeyko.com Signed-off-by: Viacheslav Dubeyko slava@dubeyko.com Link: https://lore.kernel.org/r/20250909031316.1647094-1-k.chen@smail.nju.edu.cn Signed-off-by: Viacheslav Dubeyko slava@dubeyko.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/hfsplus/dir.c | 2 +- fs/hfsplus/hfsplus_fs.h | 8 ++++++-- fs/hfsplus/unicode.c | 24 +++++++++++++++++++----- fs/hfsplus/xattr.c | 6 +++--- 4 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/fs/hfsplus/dir.c b/fs/hfsplus/dir.c index 876bbb80fb4dc..1b3e27a0d5e03 100644 --- a/fs/hfsplus/dir.c +++ b/fs/hfsplus/dir.c @@ -204,7 +204,7 @@ static int hfsplus_readdir(struct file *file, struct dir_context *ctx) fd.entrylength); type = be16_to_cpu(entry.type); len = NLS_MAX_CHARSET_SIZE * HFSPLUS_MAX_STRLEN; - err = hfsplus_uni2asc(sb, &fd.key->cat.name, strbuf, &len); + err = hfsplus_uni2asc_str(sb, &fd.key->cat.name, strbuf, &len); if (err) goto out; if (type == HFSPLUS_FOLDER) { diff --git a/fs/hfsplus/hfsplus_fs.h b/fs/hfsplus/hfsplus_fs.h index 96a5c24813dd6..2311e4be4e865 100644 --- a/fs/hfsplus/hfsplus_fs.h +++ b/fs/hfsplus/hfsplus_fs.h @@ -521,8 +521,12 @@ int hfsplus_strcasecmp(const struct hfsplus_unistr *s1, const struct hfsplus_unistr *s2); int hfsplus_strcmp(const struct hfsplus_unistr *s1, const struct hfsplus_unistr *s2); -int hfsplus_uni2asc(struct super_block *sb, const struct hfsplus_unistr *ustr, - char *astr, int *len_p); +int hfsplus_uni2asc_str(struct super_block *sb, + const struct hfsplus_unistr *ustr, char *astr, + int *len_p); +int hfsplus_uni2asc_xattr_str(struct super_block *sb, + const struct hfsplus_attr_unistr *ustr, + char *astr, int *len_p); int hfsplus_asc2uni(struct super_block *sb, struct hfsplus_unistr *ustr, int max_unistr_len, const char *astr, int len); int hfsplus_hash_dentry(const struct dentry *dentry, struct qstr *str); diff --git a/fs/hfsplus/unicode.c b/fs/hfsplus/unicode.c index 36b6cf2a3abba..862ba27f1628a 100644 --- a/fs/hfsplus/unicode.c +++ b/fs/hfsplus/unicode.c @@ -119,9 +119,8 @@ static u16 *hfsplus_compose_lookup(u16 *p, u16 cc) return NULL; }
-int hfsplus_uni2asc(struct super_block *sb, - const struct hfsplus_unistr *ustr, - char *astr, int *len_p) +static int hfsplus_uni2asc(struct super_block *sb, const struct hfsplus_unistr *ustr, + int max_len, char *astr, int *len_p) { const hfsplus_unichr *ip; struct nls_table *nls = HFSPLUS_SB(sb)->nls; @@ -134,8 +133,8 @@ int hfsplus_uni2asc(struct super_block *sb, ip = ustr->unicode;
ustrlen = be16_to_cpu(ustr->length); - if (ustrlen > HFSPLUS_MAX_STRLEN) { - ustrlen = HFSPLUS_MAX_STRLEN; + if (ustrlen > max_len) { + ustrlen = max_len; pr_err("invalid length %u has been corrected to %d\n", be16_to_cpu(ustr->length), ustrlen); } @@ -256,6 +255,21 @@ int hfsplus_uni2asc(struct super_block *sb, return res; }
+inline int hfsplus_uni2asc_str(struct super_block *sb, + const struct hfsplus_unistr *ustr, char *astr, + int *len_p) +{ + return hfsplus_uni2asc(sb, ustr, HFSPLUS_MAX_STRLEN, astr, len_p); +} + +inline int hfsplus_uni2asc_xattr_str(struct super_block *sb, + const struct hfsplus_attr_unistr *ustr, + char *astr, int *len_p) +{ + return hfsplus_uni2asc(sb, (const struct hfsplus_unistr *)ustr, + HFSPLUS_ATTR_MAX_STRLEN, astr, len_p); +} + /* * Convert one or more ASCII characters into a single unicode character. * Returns the number of ASCII characters corresponding to the unicode char. diff --git a/fs/hfsplus/xattr.c b/fs/hfsplus/xattr.c index 18dc3d254d218..c951fa9835aa1 100644 --- a/fs/hfsplus/xattr.c +++ b/fs/hfsplus/xattr.c @@ -735,9 +735,9 @@ ssize_t hfsplus_listxattr(struct dentry *dentry, char *buffer, size_t size) goto end_listxattr;
xattr_name_len = NLS_MAX_CHARSET_SIZE * HFSPLUS_ATTR_MAX_STRLEN; - if (hfsplus_uni2asc(inode->i_sb, - (const struct hfsplus_unistr *)&fd.key->attr.key_name, - strbuf, &xattr_name_len)) { + if (hfsplus_uni2asc_xattr_str(inode->i_sb, + &fd.key->attr.key_name, strbuf, + &xattr_name_len)) { pr_err("unicode conversion failed\n"); res = -EIO; goto end_listxattr;