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NFS: Be more careful about mapping file permissions

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When mapping a directory, we want the MAY_WRITE permissions to reflect
whether or not we have permission to modify, add and delete the directory
entries. MAY_EXEC must map to lookup permissions.

On the other hand, for files, we want MAY_WRITE to reflect a permission
to modify and extend the file.

Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Trond Myklebust 2017-07-11 17:54:35 -04:00 committed by Anna Schumaker
parent bd8b244174
commit ecbb903c56
1 changed files with 17 additions and 8 deletions
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25
fs/nfs/dir.c
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@ -2379,21 +2379,30 @@ EXPORT_SYMBOL_GPL(nfs_access_add_cache);
#define NFS_MAY_WRITE (NFS4_ACCESS_MODIFY | \
NFS4_ACCESS_EXTEND | \
NFS4_ACCESS_DELETE)
#define NFS_FILE_MAY_WRITE (NFS4_ACCESS_MODIFY | \
NFS4_ACCESS_EXTEND)
#define NFS_DIR_MAY_WRITE NFS_MAY_WRITE
#define NFS_MAY_LOOKUP (NFS4_ACCESS_LOOKUP)
#define NFS_MAY_EXECUTE (NFS4_ACCESS_EXECUTE)
static int
nfs_access_calc_mask(u32 access_result)
nfs_access_calc_mask(u32 access_result, umode_t umode)
{
int mask = 0;
if (access_result & NFS_MAY_READ)
mask |= MAY_READ;
if (access_result & NFS_MAY_WRITE)
mask |= MAY_WRITE;
if (access_result & NFS_MAY_LOOKUP)
mask |= MAY_EXEC;
if (access_result & NFS_MAY_EXECUTE)
mask |= MAY_EXEC;
if (S_ISDIR(umode)) {
if ((access_result & NFS_DIR_MAY_WRITE) == NFS_DIR_MAY_WRITE)
mask |= MAY_WRITE;
if ((access_result & NFS_MAY_LOOKUP) == NFS_MAY_LOOKUP)
mask |= MAY_EXEC;
} else if (S_ISREG(umode)) {
if ((access_result & NFS_FILE_MAY_WRITE) == NFS_FILE_MAY_WRITE)
mask |= MAY_WRITE;
if ((access_result & NFS_MAY_EXECUTE) == NFS_MAY_EXECUTE)
mask |= MAY_EXEC;
} else if (access_result & NFS_MAY_WRITE)
mask |= MAY_WRITE;
return mask;
}
@ -2438,7 +2447,7 @@ static int nfs_do_access(struct inode *inode, struct rpc_cred *cred, int mask)
}
nfs_access_add_cache(inode, &cache);
out_cached:
cache_mask = nfs_access_calc_mask(cache.mask);
cache_mask = nfs_access_calc_mask(cache.mask, inode->i_mode);
if ((mask & ~cache_mask & (MAY_READ | MAY_WRITE | MAY_EXEC)) != 0)
status = -EACCES;
out: