Backup errno in net_would_block

Safe and restore the value of errno in net_would_block to be sure
it's not affected by the guarding call to fcntl. Fixes #845.
This commit is contained in:
Hanno Becker 2017-05-12 16:22:21 +01:00
parent 98864d5c0b
commit cc4d80fde3
2 changed files with 12 additions and 1 deletions

View File

@ -1,5 +1,11 @@
mbed TLS ChangeLog (Sorted per branch, date)
= mbed TLS x.x.x branch released xxxx-xx-xx
Bugfix
* Fix net_would_block to avoid modification by errno through fcntl call.
Found by nkolban. Fixes #845.
= mbed TLS 1.3.19 branch released 2017-03-08
Security

View File

@ -396,13 +396,18 @@ static int net_would_block( int fd )
*/
static int net_would_block( int fd )
{
int err = errno;
/*
* Never return 'WOULD BLOCK' on a non-blocking socket
*/
if( ( fcntl( fd, F_GETFL ) & O_NONBLOCK ) != O_NONBLOCK )
{
errno = err;
return( 0 );
}
switch( errno )
switch( errno = err )
{
#if defined EAGAIN
case EAGAIN: