diff options
| author | Anton Protopopov | 2016-02-11 23:57:21 -0500 |
|---|---|---|
| committer | Theodore Ts'o | 2016-02-11 23:57:21 -0500 |
| commit | fdde368e7c2963e319f919fa57908537060847fc (patch) | |
| tree | ae2c7776127a272e876f84faff43ae0a69e100d7 /fs | |
| parent | 05145bd799e498ce4e3b5145894174ee881f02b0 (diff) | |
ext4: ioctl: fix erroneous return value
The ext4_ioctl_setflags() function which is used in the ioctls
EXT4_IOC_SETFLAGS and EXT4_IOC_FSSETXATTR may return the positive value
EPERM instead of -EPERM in case of error. This bug was introduced by a
recent commit 9b7365fc.
The following program can be used to illustrate the wrong behavior:
#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <err.h>
#define FS_IOC_GETFLAGS _IOR('f', 1, long)
#define FS_IOC_SETFLAGS _IOW('f', 2, long)
#define FS_IMMUTABLE_FL 0x00000010
int main(void)
{
int fd;
long flags;
fd = open("file", O_RDWR|O_CREAT, 0600);
if (fd < 0)
err(1, "open");
if (ioctl(fd, FS_IOC_GETFLAGS, &flags) < 0)
err(1, "ioctl: FS_IOC_GETFLAGS");
flags |= FS_IMMUTABLE_FL;
if (ioctl(fd, FS_IOC_SETFLAGS, &flags) < 0)
err(1, "ioctl: FS_IOC_SETFLAGS");
warnx("ioctl returned no error");
return 0;
}
Running it gives the following result:
$ strace -e ioctl ./test
ioctl(3, FS_IOC_GETFLAGS, 0x7ffdbd8bfd38) = 0
ioctl(3, FS_IOC_SETFLAGS, 0x7ffdbd8bfd38) = 1
test: ioctl returned no error
+++ exited with 0 +++
Running the program on a kernel with the bug fixed gives the proper result:
$ strace -e ioctl ./test
ioctl(3, FS_IOC_GETFLAGS, 0x7ffdd2768258) = 0
ioctl(3, FS_IOC_SETFLAGS, 0x7ffdd2768258) = -1 EPERM (Operation not permitted)
test: ioctl: FS_IOC_SETFLAGS: Operation not permitted
+++ exited with 1 +++
Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/ioctl.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index 0f6c36922c24..a99b010e2194 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -208,7 +208,7 @@ static int ext4_ioctl_setflags(struct inode *inode, { struct ext4_inode_info *ei = EXT4_I(inode); handle_t *handle = NULL; - int err = EPERM, migrate = 0; + int err = -EPERM, migrate = 0; struct ext4_iloc iloc; unsigned int oldflags, mask, i; unsigned int jflag; |