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EVM: prevent array underflow in evm_write_xattrs()

If the user sets xattr->name[0] to NUL then we would read one character
before the start of the array.  This bug seems harmless as far as I can
see but perhaps it would trigger a warning in KASAN.

Fixes: fa516b66a1 ("EVM: Allow runtime modification of the set of verified xattrs")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
hifive-unleashed-5.1
Dan Carpenter 2018-05-29 16:11:28 +03:00 committed by Mimi Zohar
parent 72acd64df4
commit a41d80acfa
1 changed files with 1 additions and 1 deletions

View File

@ -209,7 +209,7 @@ static ssize_t evm_write_xattrs(struct file *file, const char __user *buf,
/* Remove any trailing newline */
len = strlen(xattr->name);
if (xattr->name[len-1] == '\n')
if (len && xattr->name[len-1] == '\n')
xattr->name[len-1] = '\0';
if (strcmp(xattr->name, ".") == 0) {