]> git.baikalelectronics.ru Git - kernel.git/commit
fs/pipe.c: return error code rather than 0 in pipe_write()
authorEric Biggers <ebiggers3@gmail.com>
Sat, 17 Oct 2015 21:26:09 +0000 (16:26 -0500)
committerAl Viro <viro@zeniv.linux.org.uk>
Wed, 11 Nov 2015 07:18:26 +0000 (02:18 -0500)
commit560242290ef1f9636bc248fc0e58d49fa6fea6dc
tree284390441dc289c394630aca998ed85b36442242
parent967a1e0eed2e76be516ecf9df5efabe57b7dbf72
fs/pipe.c: return error code rather than 0 in pipe_write()

pipe_write() would return 0 if it failed to merge the beginning of the
data to write with the last, partially filled pipe buffer.  It should
return an error code instead.  Userspace programs could be confused by
write() returning 0 when called with a nonzero 'count'.

The EFAULT error case was a regression from 67785d8ff8 ("new helper:
copy_page_from_iter()"), while the ops->confirm() error case was a much
older bug.

Test program:

#include <assert.h>
#include <errno.h>
#include <unistd.h>

int main(void)
{
int fd[2];
char data[1] = {0};

assert(0 == pipe(fd));
assert(1 == write(fd[1], data, 1));

/* prior to this patch, write() returned 0 here  */
assert(-1 == write(fd[1], NULL, 1));
assert(errno == EFAULT);
}

Cc: stable@vger.kernel.org # at least v3.15+
Signed-off-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
fs/pipe.c