Messages in this thread Patch in this message | | | From | Li Wang <> | Subject | [PATCH v2] vfs: fix put_compat_statfs64() does not handle errors | Date | Tue, 15 Nov 2016 17:19:01 +0800 |
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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@redhat.com> --- 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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