Acorrding to Matthieu Herrb's test cases, a new created file will
get a bad mode as 0666 (expected 0644) after commit dff25ddb4808
"nfs: add support for the umask attribute".
It is caused by missing check of FATTR4_WORD2_MODE_UMASK
in nfs4_exclusive_attrset.
#include <sys/types.h>
#include <sys/stat.h>
#include <err.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
/*
* Demonstrate file creation bug on NFS v4 and linux kernel 4.4+
*
* mktemp() is used on purpose.
*/
int
main(int argc, char *argv[])
{
const char *name = argv[1];
char tmp[] = "./tmpXXXXXXXXXX";
struct stat buf;
mode_t expected;
int fd, i, n = 40;
umask(S_IWGRP | S_IWOTH);
expected = 0666 & ~(S_IWGRP | S_IWOTH);
if (argv[1] == NULL)
name = mktemp(tmp);
for (i = 0; i < n; i++) {
fd = open(name, O_RDWR|O_CREAT|O_EXCL, 0666);
if (fd < 0)
err(1, "open %s", name);
memset(&buf, 0, sizeof(buf));
if (stat(name, &buf) < 0)
err(1, "stat %s", name);
if ((buf.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO)) != expected)
printf("%s: %o\n", name,
(int)buf.st_mode & (S_IRWXU|S_IRWXG|S_IRWXO));
else
printf("%s: ok\n", name);
unlink(name);
}
exit(0);
}
Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
---
fs/nfs/nfs4proc.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 6dcbc5d..a3e9ef1 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -2697,7 +2697,8 @@ static inline void nfs4_exclusive_attrset(struct nfs4_opendata *opendata,
sattr->ia_valid |= ATTR_MTIME;
/* Except MODE, it seems harmless of setting twice. */
- if ((attrset[1] & FATTR4_WORD1_MODE))
+ if ((attrset[1] & FATTR4_WORD1_MODE) ||
+ (attrset[2] & FATTR4_WORD2_MODE_UMASK))
sattr->ia_valid &= ~ATTR_MODE;
if (attrset[2] & FATTR4_WORD2_SECURITY_LABEL)
--
2.9.3
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