From: Helge Deller <deller@xxxxxx> Subject: fs/signalfd.c: fix inconsistent return codes for signalfd4 The kernel signalfd4() syscall returns different error codes when called either in compat or native mode. This behaviour makes correct emulation in qemu and testing programs like LTP more complicated. Fix the code to always return -in both modes- EFAULT for unaccessible user memory, and EINVAL when called with an invalid signal mask. Link: http://lkml.kernel.org/r/20200530100707.GA10159@xxxxxxxxxxxxxxxx Signed-off-by: Helge Deller <deller@xxxxxx> Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Laurent Vivier <laurent@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/signalfd.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) --- a/fs/signalfd.c~fs-signalfdc-fix-inconsistent-return-codes-for-signalfd4 +++ a/fs/signalfd.c @@ -314,9 +314,10 @@ SYSCALL_DEFINE4(signalfd4, int, ufd, sig { sigset_t mask; - if (sizemask != sizeof(sigset_t) || - copy_from_user(&mask, user_mask, sizeof(mask))) + if (sizemask != sizeof(sigset_t)) return -EINVAL; + if (copy_from_user(&mask, user_mask, sizeof(mask))) + return -EFAULT; return do_signalfd4(ufd, &mask, flags); } @@ -325,9 +326,10 @@ SYSCALL_DEFINE3(signalfd, int, ufd, sigs { sigset_t mask; - if (sizemask != sizeof(sigset_t) || - copy_from_user(&mask, user_mask, sizeof(mask))) + if (sizemask != sizeof(sigset_t)) return -EINVAL; + if (copy_from_user(&mask, user_mask, sizeof(mask))) + return -EFAULT; return do_signalfd4(ufd, &mask, 0); } _
