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vfs: fix preadv64v2 and pwritev64v2 compat syscalls with offset == -1

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[ Upstream commit cc4b1242d7e3b42eed73881fc749944146493e4f ]

The preadv2 and pwritev2 syscalls are supposed to emulate the readv and
writev syscalls when offset == -1. Therefore the compat code should
check for offset before calling do_compat_preadv64 and
do_compat_pwritev64. This is the case for the preadv2 and pwritev2
syscalls, but handling of offset == -1 is missing in their 64-bit
equivalent.

This patch fixes that, calling do_compat_readv and do_compat_writev when
offset == -1. This fixes the following glibc tests on x32:
 - misc/tst-preadvwritev2
 - misc/tst-preadvwritev64v2

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Aurelien Jarno 2018-12-06 20:05:34 +01:00 committed by Greg Kroah-Hartman
parent 97ac96eec6
commit 24c6f9fdf8
1 changed files with 6 additions and 0 deletions
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6
fs/read_write.c
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@ -1204,6 +1204,9 @@ COMPAT_SYSCALL_DEFINE5(preadv64v2, unsigned long, fd,
const struct compat_iovec __user *,vec,
unsigned long, vlen, loff_t, pos, int, flags)
{
if (pos == -1)
return do_compat_readv(fd, vec, vlen, flags);
return do_compat_preadv64(fd, vec, vlen, pos, flags);
}
#endif
@ -1310,6 +1313,9 @@ COMPAT_SYSCALL_DEFINE5(pwritev64v2, unsigned long, fd,
const struct compat_iovec __user *,vec,
unsigned long, vlen, loff_t, pos, int, flags)
{
if (pos == -1)
return do_compat_writev(fd, vec, vlen, flags);
return do_compat_pwritev64(fd, vec, vlen, pos, flags);
}
#endif