btrfs: return EINVAL if start > total_bytes in fitrim ioctl

PATCH In review Lukas Czerner 2 participants 2 messages Sep 5, 2011 – Sep 22, 2011 Btrfs file system

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Lukas Czerner

author

2011-09-05 14:34 UTC #0 lore raw

PATCH 1/1 btrfs: return EINVAL if start > total_bytes in fitrim ioctl

We should retirn EINVAL if the start is beyond the end of the file system in the btrfs_ioctl_fitrim(). Fix that by adding the appropriate check for it.

Also in the btrfs_trim_fs() it is possible that len+start might overflow if big values are passed. Fix it by decrementing the len so that start+len is equal to the file system size in the worst case.

Signed-off-by Lukas Czerner <[email protected]>

---
 fs/btrfs/ioctl.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

fs/btrfs/ioctl.c +5 -1

index 970977a..ad890ee 100644
@@ -277,6 +277,7 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 	struct fstrim_range range;
 	u64 minlen = ULLONG_MAX;
 	u64 num_devices = 0;
+	u64 total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 	int ret;
 
 	if (!capable(CAP_SYS_ADMIN))

@@ -295,12 +296,15 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 		}
 	}
 	rcu_read_unlock();
+
 	if (!num_devices)
 		return -EOPNOTSUPP;
-
 	if (copy_from_user(&range, arg, sizeof(range)))
 		return -EFAULT;
+	if (range.start > total_bytes)
+		return -EINVAL;
 
+	range.len = min(range.len, total_bytes - range.start);
 	range.minlen = max(range.minlen, minlen);
 	ret = btrfs_trim_fs(root, &range);
 	if (ret < 0)

Signature · 1 line

1.7.4.4

David Sterba

Reviewed-by on v1 1/1

2011-09-22 10:15 UTC #1 lore raw

Quoted 9 lines · Lukas Czerner

We should retirn EINVAL if the start is beyond the end of the file system in the btrfs_ioctl_fitrim(). Fix that by adding the appropriate check for it.
Also in the btrfs_trim_fs() it is possible that len+start might overflow if big values are passed. Fix it by decrementing the len so that start+len is equal to the file system size in the worst case.
Signed-off-by Lukas Czerner <[email protected]>

Reviewed-by David Sterba <[email protected]>

Quoted 40 lines

---
 fs/btrfs/ioctl.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

fs/btrfs/ioctl.c +5 -1

index 970977a..ad890ee 100644
@@ -277,6 +277,7 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 	struct fstrim_range range;
 	u64 minlen = ULLONG_MAX;
 	u64 num_devices = 0;
+	u64 total_bytes = btrfs_super_total_bytes(&root->fs_info->super_copy);
 	int ret;
 
 	if (!capable(CAP_SYS_ADMIN))

@@ -295,12 +296,15 @@ static noinline int btrfs_ioctl_fitrim(struct file *file, void __user *arg)
 		}
 	}
 	rcu_read_unlock();
+
 	if (!num_devices)
 		return -EOPNOTSUPP;
-
 	if (copy_from_user(&range, arg, sizeof(range)))
 		return -EFAULT;
+	if (range.start > total_bytes)
+		return -EINVAL;
 
+	range.len = min(range.len, total_bytes - range.start);
 	range.minlen = max(range.minlen, minlen);
 	ret = btrfs_trim_fs(root, &range);
 	if (ret < 0)

Signature · 6 lines

1.7.4.4

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