put_compat_statfs64() does NOT return -1 and setting errno to EOVERFLOW
when some variables(like: f_bsize) overflowed in the returned struct.
The reason is that the ubuf->f_blocks is __u64 type, it couldn't be
4bits as the judgement in put_comat_statfs64(). Here correct the
__u32 variables(in struct compat_statfs64) for comparison.
reproducer:
step1. mount hugetlbfs with two different pagesize on ppc64 arch.
$ hugeadm --pool-pages-max 16M:0
$ hugeadm --create-mount
$ mount | grep -i hugetlbfs
none on /var/lib/hugetlbfs/pagesize-16MB type hugetlbfs (rw,relatime,seclabel,pagesize=16777216)
none on /var/lib/hugetlbfs/pagesize-16GB type hugetlbfs (rw,relatime,seclabel,pagesize=17179869184)
step2. compile & run this C program.
$ cat statfs64_test.c
#define _LARGEFILE64_SOURCE
#include <stdio.h>
#include <sys/syscall.h>
#include <sys/statfs.h>
int main()
{
struct statfs64 sb;
int err;
err = syscall(SYS_statfs64, "/var/lib/hugetlbfs/pagesize-16GB", sizeof(sb), &sb);
if (err)
return -1;
printf("sizeof f_bsize = %d, f_bsize=%ld\n", sizeof(sb.f_bsize), sb.f_bsize);
return 0;
}
$ gcc -m32 statfs64_test.c
$ ./a.out
sizeof f_bsize = 4, f_bsize=0
Signed-off-by: Li Wang <liwang@xxxxxxxxxx>
---
fs/compat.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/fs/compat.c b/fs/compat.c
index bd064a2..543b48c 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -253,9 +253,9 @@ static int put_compat_statfs(struct compat_statfs __user *ubuf, struct kstatfs *
static int put_compat_statfs64(struct compat_statfs64 __user *ubuf, struct kstatfs *kbuf)
{
- if (sizeof ubuf->f_blocks == 4) {
- if ((kbuf->f_blocks | kbuf->f_bfree | kbuf->f_bavail |
- kbuf->f_bsize | kbuf->f_frsize) & 0xffffffff00000000ULL)
+ if (sizeof(ubuf->f_bsize) == 4) {
+ if ((kbuf->f_type | kbuf->f_bsize | kbuf->f_namelen |
+ kbuf->f_frsize | kbuf->f_flags) & 0xffffffff00000000ULL)
return -EOVERFLOW;
/* f_files and f_ffree may be -1; it's okay
* to stuff that into 32 bits */
--
1.8.3.1
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