[PATCH] eCryptfs: fix a couple type promotion bugs

[PATCH] eCryptfs: fix a couple type promotion bugs

[Dan Carpenter]

ECRYPTFS_SIZE_AND_MARKER_BYTES is type size_t, so if "rc" is negative
that gets type promoted to a high positive value and treated as success.

Fixes: 778aeb42a708 ("eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose()")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
index 4dd842f72846..506f2a0bba41 100644
--- a/fs/ecryptfs/crypto.c
+++ b/fs/ecryptfs/crypto.c
@@ -1018,8 +1018,10 @@ int ecryptfs_read_and_validate_header_region(struct inode *inode)
 
 	rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
 				 inode);
+	if (rc < 0)
+		return rc;
 	if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
-		return rc >= 0 ? -EINVAL : rc;
+		return -EINVAL;
 	rc = ecryptfs_validate_marker(marker);
 	if (!rc)
 		ecryptfs_i_size_init(file_size, inode);
@@ -1381,8 +1383,10 @@ int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
 				     ecryptfs_inode_to_lower(inode),
 				     ECRYPTFS_XATTR_NAME, file_size,
 				     ECRYPTFS_SIZE_AND_MARKER_BYTES);
+	if (rc < 0)
+		return rc;
 	if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
-		return rc >= 0 ? -EINVAL : rc;
+		return -EINVAL;
 	rc = ecryptfs_validate_marker(marker);
 	if (!rc)
 		ecryptfs_i_size_init(file_size, inode);

Re: [PATCH] eCryptfs: fix a couple type promotion bugs

[Tyler Hicks]

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On 2018-07-04 12:35:56, Dan Carpenter wrote:
> ECRYPTFS_SIZE_AND_MARKER_BYTES is type size_t, so if "rc" is negative
> that gets type promoted to a high positive value and treated as success.
> 
> Fixes: 778aeb42a708 ("eCryptfs: Cleanup and optimize ecryptfs_lookup_interpose()")
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Thanks, Dan!

I made a small change to use "if/else if" rather than "if/if". I've
pushed the patch to the ecryptfs next branch.

Tyler

> 
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index 4dd842f72846..506f2a0bba41 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -1018,8 +1018,10 @@ int ecryptfs_read_and_validate_header_region(struct inode *inode)
>  
>  	rc = ecryptfs_read_lower(file_size, 0, ECRYPTFS_SIZE_AND_MARKER_BYTES,
>  				 inode);
> +	if (rc < 0)
> +		return rc;
>  	if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
> -		return rc >= 0 ? -EINVAL : rc;
> +		return -EINVAL;
>  	rc = ecryptfs_validate_marker(marker);
>  	if (!rc)
>  		ecryptfs_i_size_init(file_size, inode);
> @@ -1381,8 +1383,10 @@ int ecryptfs_read_and_validate_xattr_region(struct dentry *dentry,
>  				     ecryptfs_inode_to_lower(inode),
>  				     ECRYPTFS_XATTR_NAME, file_size,
>  				     ECRYPTFS_SIZE_AND_MARKER_BYTES);
> +	if (rc < 0)
> +		return rc;
>  	if (rc < ECRYPTFS_SIZE_AND_MARKER_BYTES)
> -		return rc >= 0 ? -EINVAL : rc;
> +		return -EINVAL;
>  	rc = ecryptfs_validate_marker(marker);
>  	if (!rc)
>  		ecryptfs_i_size_init(file_size, inode);
> --
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