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-rw-r--r--fs/compat.c22
1 files changed, 18 insertions, 4 deletions
diff --git a/fs/compat.c b/fs/compat.c
index 55ac0324aaf1..271b75d1597f 100644
--- a/fs/compat.c
+++ b/fs/compat.c
@@ -494,9 +494,21 @@ asmlinkage long compat_sys_fcntl64(unsigned int fd, unsigned int cmd,
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))
+ /* GETLK was successfule and we need to return the data...
+ * but it needs to fit in the compat structure.
+ * l_start shouldn't be too big, unless the original
+ * start + end is greater than COMPAT_OFF_T_MAX, in which
+ * case the app was asking for trouble, so we return
+ * -EOVERFLOW in that case.
+ * l_len could be too big, in which case we just truncate it,
+ * and only allow the app to see that part of the conflicting
+ * lock that might make sense to it anyway
+ */
+
+ if (f.l_start > COMPAT_OFF_T_MAX)
ret = -EOVERFLOW;
+ if (f.l_len > COMPAT_OFF_T_MAX)
+ f.l_len = COMPAT_OFF_T_MAX;
if (ret == 0)
ret = put_compat_flock(&f, compat_ptr(arg));
}
@@ -515,9 +527,11 @@ asmlinkage long compat_sys_fcntl64(unsigned int fd, unsigned int cmd,
(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))
+ /* need to return lock information - see above for commentary */
+ if (f.l_start > COMPAT_LOFF_T_MAX)
ret = -EOVERFLOW;
+ if (f.l_len > COMPAT_LOFF_T_MAX)
+ f.l_len = COMPAT_LOFF_T_MAX;
if (ret == 0)
ret = put_compat_flock64(&f, compat_ptr(arg));
}