compat fcntl errors

From: Olaf Hering
Date: Wed Sep 21 2005 - 10:54:31 EST



This testcase fron ltp fails as 32bit binary on ppc64.
./testcases/network/nfs/cthon04/lock/tlock.c

fcntl(): Value too large for defined data type

Possible patch below.

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>

int main(int argc, char *argv[])
{
int fd = open(argv[1], O_RDWR | O_CREAT, 0666);
struct flock fl;
off_t maxeof;

memset(&fl, 0, sizeof(struct flock));
// test 1.6 of cthon04 locking tests
maxeof = (off_t)1 << (sizeof (off_t) * 8 - 2);
maxeof += maxeof - 1;
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 1;
fl.l_len = maxeof;
if (fcntl(fd, F_GETLK, &fl) < 0) {
perror("fcntl()");
exit(1);
}
printf("test 1.6 passes\n");

close(fd);
return 0;
}

fs/compat.c | 30 ++++++++++++++++--------------
fs/locks.c | 3 ++-
2 files changed, 18 insertions(+), 15 deletions(-)

Index: linux-2.6.13.cthon04/fs/compat.c
===================================================================
--- linux-2.6.13.cthon04.orig/fs/compat.c
+++ linux-2.6.13.cthon04/fs/compat.c
@@ -584,17 +584,18 @@ asmlinkage long compat_sys_fcntl64(unsig
ret = get_compat_flock(&f, compat_ptr(arg));
if (ret != 0)
break;
+ if ((cmd == F_GETLK) &&
+ ((f.l_start > COMPAT_OFF_T_MAX) ||
+ ((f.l_start + f.l_len - 1) > COMPAT_OFF_T_MAX))) {
+ ret = -EOVERFLOW;
+ break;
+ }
old_fs = get_fs();
set_fs(KERNEL_DS);
ret = sys_fcntl(fd, cmd, (unsigned long)&f);
set_fs(old_fs);
- if (cmd == F_GETLK && ret == 0) {
- if ((f.l_start >= COMPAT_OFF_T_MAX) ||
- ((f.l_start + f.l_len) > COMPAT_OFF_T_MAX))
- ret = -EOVERFLOW;
- if (ret == 0)
- ret = put_compat_flock(&f, compat_ptr(arg));
- }
+ if (cmd == F_GETLK && ret == 0)
+ ret = put_compat_flock(&f, compat_ptr(arg));
break;

case F_GETLK64:
@@ -603,19 +604,20 @@ asmlinkage long compat_sys_fcntl64(unsig
ret = get_compat_flock64(&f, compat_ptr(arg));
if (ret != 0)
break;
+ if ((cmd == F_GETLK64) &&
+ ((f.l_start > COMPAT_LOFF_T_MAX) ||
+ ((f.l_start + f.l_len - 1) > COMPAT_LOFF_T_MAX))) {
+ ret = -EOVERFLOW;
+ break;
+ }
old_fs = get_fs();
set_fs(KERNEL_DS);
ret = sys_fcntl(fd, (cmd == F_GETLK64) ? F_GETLK :
((cmd == F_SETLK64) ? F_SETLK : F_SETLKW),
(unsigned long)&f);
set_fs(old_fs);
- if (cmd == F_GETLK64 && ret == 0) {
- if ((f.l_start >= COMPAT_LOFF_T_MAX) ||
- ((f.l_start + f.l_len) > COMPAT_LOFF_T_MAX))
- ret = -EOVERFLOW;
- if (ret == 0)
- ret = put_compat_flock64(&f, compat_ptr(arg));
- }
+ if (cmd == F_GETLK64 && ret == 0)
+ ret = put_compat_flock64(&f, compat_ptr(arg));
break;

default:
Index: linux-2.6.13.cthon04/fs/locks.c
===================================================================
--- linux-2.6.13.cthon04.orig/fs/locks.c
+++ linux-2.6.13.cthon04/fs/locks.c
@@ -314,7 +314,8 @@ static int flock_to_posix_lock(struct fi

/* POSIX-1996 leaves the case l->l_len < 0 undefined;
POSIX-2001 defines it. */
- start += l->l_start;
+ if ((start += l->l_start) < 0)
+ return -EINVAL;
end = start + l->l_len - 1;
if (l->l_len < 0) {
end = start - 1;

-
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