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authorAl Viro <viro@zeniv.linux.org.uk>2020-06-03 09:48:36 +0900
committerNamjae Jeon <namjae.jeon@samsung.com>2020-06-09 16:50:02 +0900
commitf341a7d8dcc4e3d01544d7bc145633f062ef6249 (patch)
tree7fb2b23b15196a013971bc5b79ee8ded405aaf3c /fs/exfat
parentf78059805fb9fc5c343e89f39cf11856d047dd60 (diff)
exfat: fix memory leak in exfat_parse_param()
butt3rflyh4ck reported memory leak found by syzkaller. A param->string held by exfat_mount_options. BUG: memory leak unreferenced object 0xffff88801972e090 (size 8): comm "syz-executor.2", pid 16298, jiffies 4295172466 (age 14.060s) hex dump (first 8 bytes): 6b 6f 69 38 2d 75 00 00 koi8-u.. backtrace: [<000000005bfe35d6>] kstrdup+0x36/0x70 mm/util.c:60 [<0000000018ed3277>] exfat_parse_param+0x160/0x5e0 fs/exfat/super.c:276 [<000000007680462b>] vfs_parse_fs_param+0x2b4/0x610 fs/fs_context.c:147 [<0000000097c027f2>] vfs_parse_fs_string+0xe6/0x150 fs/fs_context.c:191 [<00000000371bf78f>] generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:231 [<000000005ce5eb1b>] do_new_mount fs/namespace.c:2812 [inline] [<000000005ce5eb1b>] do_mount+0x12bb/0x1b30 fs/namespace.c:3141 [<00000000b642040c>] __do_sys_mount fs/namespace.c:3350 [inline] [<00000000b642040c>] __se_sys_mount fs/namespace.c:3327 [inline] [<00000000b642040c>] __x64_sys_mount+0x18f/0x230 fs/namespace.c:3327 [<000000003b024e98>] do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295 [<00000000ce2b698c>] entry_SYSCALL_64_after_hwframe+0x49/0xb3 exfat_free() should call exfat_free_iocharset(), to prevent a leak in case we fail after parsing iocharset= but before calling get_tree_bdev(). Additionally, there's no point copying param->string in exfat_parse_param() - just steal it, leaving NULL in param->string. That's independent from the leak or fix thereof - it's simply avoiding an extra copy. Fixes: 719c1e182916 ("exfat: add super block operations") Cc: stable@vger.kernel.org # v5.7 Reported-by: butt3rflyh4ck <butterflyhuangxx@gmail.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Diffstat (limited to 'fs/exfat')
-rw-r--r--fs/exfat/super.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/exfat/super.c b/fs/exfat/super.c
index 405717e4e3ea..e650e65536f8 100644
--- a/fs/exfat/super.c
+++ b/fs/exfat/super.c
@@ -273,9 +273,8 @@ static int exfat_parse_param(struct fs_context *fc, struct fs_parameter *param)
break;
case Opt_charset:
exfat_free_iocharset(sbi);
- opts->iocharset = kstrdup(param->string, GFP_KERNEL);
- if (!opts->iocharset)
- return -ENOMEM;
+ opts->iocharset = param->string;
+ param->string = NULL;
break;
case Opt_errors:
opts->errors = result.uint_32;
@@ -686,7 +685,12 @@ static int exfat_get_tree(struct fs_context *fc)
static void exfat_free(struct fs_context *fc)
{
- kfree(fc->s_fs_info);
+ struct exfat_sb_info *sbi = fc->s_fs_info;
+
+ if (sbi) {
+ exfat_free_iocharset(sbi);
+ kfree(sbi);
+ }
}
static const struct fs_context_operations exfat_context_ops = {