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* exfat: check if cluster num is valid
@ 2022-05-31 15:53 Tadeusz Struk
  2022-05-31 15:56 ` [PATCH v5.15] " Tadeusz Struk
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Tadeusz Struk @ 2022-05-31 15:53 UTC (permalink / raw)
  To: stable; +Cc: Namjae Jeon, Sungjong Seo, linux-fsdevel

Hi,
Please apply upstream commit: 64ba4b15e5c0 ("exfat: check if cluster num is valid")
to stable 5.18.y and 5.17.y
Backports for 5.15.y and 5.10.y will follow soon.

-- 
Thanks,
Tadeusz

^ permalink raw reply	[flat|nested] 4+ messages in thread
* [PATCH v5.15] exfat: check if cluster num is valid
  2022-05-31 15:53 exfat: check if cluster num is valid Tadeusz Struk
@ 2022-05-31 15:56 ` Tadeusz Struk
  2022-05-31 15:56 ` [PATCH v5.10] " Tadeusz Struk
  2022-06-03 14:41 ` Greg KH
  2 siblings, 0 replies; 4+ messages in thread
From: Tadeusz Struk @ 2022-05-31 15:56 UTC (permalink / raw)
  To: stable
  Cc: Tadeusz Struk, syzbot+a4087e40b9c13aad7892, Sungjong Seo, Namjae Jeon

Upstream commit: 64ba4b15e5c0 ("exfat: check if cluster num is valid")

Syzbot reported slab-out-of-bounds read in exfat_clear_bitmap.
This was triggered by reproducer calling truncute with size 0,
which causes the following trace:

BUG: KASAN: slab-out-of-bounds in exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
Read of size 8 at addr ffff888115aa9508 by task syz-executor251/365

Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3c0 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
 exfat_free_cluster+0x25a/0x4a0 fs/exfat/fatent.c:181
 __exfat_truncate+0x99e/0xe00 fs/exfat/file.c:217
 exfat_truncate+0x11b/0x4f0 fs/exfat/file.c:243
 exfat_setattr+0xa03/0xd40 fs/exfat/file.c:339
 notify_change+0xb76/0xe10 fs/attr.c:336
 do_truncate+0x1ea/0x2d0 fs/open.c:65

Move the is_valid_cluster() helper from fatent.c to a common
header to make it reusable in other *.c files. And add is_valid_cluster()
to validate if cluster number is within valid range in exfat_clear_bitmap()
and exfat_set_bitmap().

Link: https://syzkaller.appspot.com/bug?id=50381fc73821ecae743b8cf24b4c9a04776f767c
Reported-by: syzbot+a4087e40b9c13aad7892@syzkaller.appspotmail.com
Fixes: 1e49a94cf707 ("exfat: add bitmap operations")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/exfat/balloc.c   | 8 ++++++--
 fs/exfat/exfat_fs.h | 8 ++++++++
 fs/exfat/fatent.c   | 8 --------
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
index cc5cffc4a769..e2113e0a848c 100644
--- a/fs/exfat/balloc.c
+++ b/fs/exfat/balloc.c
@@ -148,7 +148,9 @@ int exfat_set_bitmap(struct inode *inode, unsigned int clu, bool sync)
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 
-	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
+	if (!is_valid_cluster(sbi, clu))
+		return -EINVAL;
+
 	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
@@ -166,7 +168,9 @@ void exfat_clear_bitmap(struct inode *inode, unsigned int clu, bool sync)
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_mount_options *opts = &sbi->options;
 
-	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
+	if (!is_valid_cluster(sbi, clu))
+		return;
+
 	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index 1d6da61157c9..9f82a8a835ee 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -381,6 +381,14 @@ static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
 		EXFAT_RESERVED_CLUSTERS;
 }
 
+static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
+		unsigned int clus)
+{
+	if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus)
+		return false;
+	return true;
+}
+
 /* super.c */
 int exfat_set_volume_dirty(struct super_block *sb);
 int exfat_clear_volume_dirty(struct super_block *sb);
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
index e949e563443c..421c27353104 100644
--- a/fs/exfat/fatent.c
+++ b/fs/exfat/fatent.c
@@ -81,14 +81,6 @@ int exfat_ent_set(struct super_block *sb, unsigned int loc,
 	return 0;
 }
 
-static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
-		unsigned int clus)
-{
-	if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus)
-		return false;
-	return true;
-}
-
 int exfat_ent_get(struct super_block *sb, unsigned int loc,
 		unsigned int *content)
 {
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* [PATCH v5.10] exfat: check if cluster num is valid
  2022-05-31 15:53 exfat: check if cluster num is valid Tadeusz Struk
  2022-05-31 15:56 ` [PATCH v5.15] " Tadeusz Struk
@ 2022-05-31 15:56 ` Tadeusz Struk
  2022-06-03 14:41 ` Greg KH
  2 siblings, 0 replies; 4+ messages in thread
From: Tadeusz Struk @ 2022-05-31 15:56 UTC (permalink / raw)
  To: stable
  Cc: Tadeusz Struk, syzbot+a4087e40b9c13aad7892, Sungjong Seo, Namjae Jeon

Upstream commit: 64ba4b15e5c0 ("exfat: check if cluster num is valid")

Syzbot reported slab-out-of-bounds read in exfat_clear_bitmap.
This was triggered by reproducer calling truncute with size 0,
which causes the following trace:

BUG: KASAN: slab-out-of-bounds in exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
Read of size 8 at addr ffff888115aa9508 by task syz-executor251/365

Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118
 print_address_description+0x81/0x3c0 mm/kasan/report.c:233
 __kasan_report mm/kasan/report.c:419 [inline]
 kasan_report+0x1a4/0x1f0 mm/kasan/report.c:436
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report_generic.c:309
 exfat_clear_bitmap+0x147/0x490 fs/exfat/balloc.c:174
 exfat_free_cluster+0x25a/0x4a0 fs/exfat/fatent.c:181
 __exfat_truncate+0x99e/0xe00 fs/exfat/file.c:217
 exfat_truncate+0x11b/0x4f0 fs/exfat/file.c:243
 exfat_setattr+0xa03/0xd40 fs/exfat/file.c:339
 notify_change+0xb76/0xe10 fs/attr.c:336
 do_truncate+0x1ea/0x2d0 fs/open.c:65

Move the is_valid_cluster() helper from fatent.c to a common
header to make it reusable in other *.c files. And add is_valid_cluster()
to validate if cluster number is within valid range in exfat_clear_bitmap()
and exfat_set_bitmap().

Link: https://syzkaller.appspot.com/bug?id=50381fc73821ecae743b8cf24b4c9a04776f767c
Reported-by: syzbot+a4087e40b9c13aad7892@syzkaller.appspotmail.com
Fixes: 1e49a94cf707 ("exfat: add bitmap operations")
Cc: stable@vger.kernel.org # v5.7+
Signed-off-by: Tadeusz Struk <tadeusz.struk@linaro.org>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
 fs/exfat/balloc.c   | 8 ++++++--
 fs/exfat/exfat_fs.h | 8 ++++++++
 fs/exfat/fatent.c   | 8 --------
 3 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/fs/exfat/balloc.c b/fs/exfat/balloc.c
index 579c10f57c2b..258b6bb5762a 100644
--- a/fs/exfat/balloc.c
+++ b/fs/exfat/balloc.c
@@ -148,7 +148,9 @@ int exfat_set_bitmap(struct inode *inode, unsigned int clu)
 	struct super_block *sb = inode->i_sb;
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 
-	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
+	if (!is_valid_cluster(sbi, clu))
+		return -EINVAL;
+
 	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
@@ -166,7 +168,9 @@ void exfat_clear_bitmap(struct inode *inode, unsigned int clu)
 	struct exfat_sb_info *sbi = EXFAT_SB(sb);
 	struct exfat_mount_options *opts = &sbi->options;
 
-	WARN_ON(clu < EXFAT_FIRST_CLUSTER);
+	if (!is_valid_cluster(sbi, clu))
+		return;
+
 	ent_idx = CLUSTER_TO_BITMAP_ENT(clu);
 	i = BITMAP_OFFSET_SECTOR_INDEX(sb, ent_idx);
 	b = BITMAP_OFFSET_BIT_IN_SECTOR(sb, ent_idx);
diff --git a/fs/exfat/exfat_fs.h b/fs/exfat/exfat_fs.h
index b8f0e829ecbd..0d139c7d150d 100644
--- a/fs/exfat/exfat_fs.h
+++ b/fs/exfat/exfat_fs.h
@@ -380,6 +380,14 @@ static inline int exfat_sector_to_cluster(struct exfat_sb_info *sbi,
 		EXFAT_RESERVED_CLUSTERS;
 }
 
+static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
+		unsigned int clus)
+{
+	if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus)
+		return false;
+	return true;
+}
+
 /* super.c */
 int exfat_set_volume_dirty(struct super_block *sb);
 int exfat_clear_volume_dirty(struct super_block *sb);
diff --git a/fs/exfat/fatent.c b/fs/exfat/fatent.c
index c3c9afee7418..a1481e47a761 100644
--- a/fs/exfat/fatent.c
+++ b/fs/exfat/fatent.c
@@ -81,14 +81,6 @@ int exfat_ent_set(struct super_block *sb, unsigned int loc,
 	return 0;
 }
 
-static inline bool is_valid_cluster(struct exfat_sb_info *sbi,
-		unsigned int clus)
-{
-	if (clus < EXFAT_FIRST_CLUSTER || sbi->num_clusters <= clus)
-		return false;
-	return true;
-}
-
 int exfat_ent_get(struct super_block *sb, unsigned int loc,
 		unsigned int *content)
 {
-- 
2.36.1


^ permalink raw reply related	[flat|nested] 4+ messages in thread
* Re: exfat: check if cluster num is valid
  2022-05-31 15:53 exfat: check if cluster num is valid Tadeusz Struk
  2022-05-31 15:56 ` [PATCH v5.15] " Tadeusz Struk
  2022-05-31 15:56 ` [PATCH v5.10] " Tadeusz Struk
@ 2022-06-03 14:41 ` Greg KH
  2 siblings, 0 replies; 4+ messages in thread
From: Greg KH @ 2022-06-03 14:41 UTC (permalink / raw)
  To: Tadeusz Struk; +Cc: stable, Namjae Jeon, Sungjong Seo, linux-fsdevel

On Tue, May 31, 2022 at 08:53:40AM -0700, Tadeusz Struk wrote:
> Hi,
> Please apply upstream commit: 64ba4b15e5c0 ("exfat: check if cluster num is valid")
> to stable 5.18.y and 5.17.y
> Backports for 5.15.y and 5.10.y will follow soon.

All now queued up, thanks.

greg k-h

^ permalink raw reply	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-06-03 14:41 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2022-05-31 15:53 exfat: check if cluster num is valid Tadeusz Struk
2022-05-31 15:56 ` [PATCH v5.15] " Tadeusz Struk
2022-05-31 15:56 ` [PATCH v5.10] " Tadeusz Struk
2022-06-03 14:41 ` Greg KH

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