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Commit 4fd8da8d62416d0dae05603ab5990a498d9aeb12

Authored by Heiko Carstens
Committed by Linus Torvalds
1 parent a6e995ad74
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

fs: change sys_truncate length parameter type 

For this system call user space passes a signed long length parameter,
while the kernel side takes an unsigned long parameter and converts it
later to signed long again.

This has led to bugs in compat wrappers see e.g.  dd90bbd5 "powerpc: Add
compat_sys_truncate".  The s390 compat wrapper for this functions is
broken as well since it also performs zero extension instead of sign
extension for the length parameter.

In addition if hpa comes up with an automated way of generating
compat wrappers it would generate a wrong one here.

So change the length parameter from unsigned long to long.

Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 2 changed files with 3 additions and 5 deletions Side-by-side Diff

... ... @@ -290,10 +290,9 @@
290 290 return error;
291 291 }
292 292  
293   -SYSCALL_DEFINE2(truncate, const char __user *, path, unsigned long, length)
  293 +SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
294 294 {
295   - /* on 32-bit boxen it will cut the range 2^31--2^32-1 off */
296   - return do_sys_truncate(path, (long)length);
  295 + return do_sys_truncate(path, length);
297 296 }
298 297  
299 298 static long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
include/linux/syscalls.h
Diff comments   View file @ 4fd8da8
... ... @@ -460,8 +460,7 @@
460 460 void __user *data);
461 461 asmlinkage long sys_umount(char __user *name, int flags);
462 462 asmlinkage long sys_oldumount(char __user *name);
463   -asmlinkage long sys_truncate(const char __user *path,
464   - unsigned long length);
  463 +asmlinkage long sys_truncate(const char __user *path, long length);
465 464 asmlinkage long sys_ftruncate(unsigned int fd, unsigned long length);
466 465 asmlinkage long sys_stat(char __user *filename,
467 466 struct __old_kernel_stat __user *statbuf);