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pselect6() and friends: take handling the combined 6th/7th args into helper 

... and use unsafe_get_user(), while we are at it.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2020-02-19 09:54:24 -05:00
parent b44f687386
commit 7e71609f64
1 changed files with 60 additions and 44 deletions
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104
fs/select.c
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@ -766,22 +766,38 @@ static long do_pselect(int n, fd_set __user *inp, fd_set __user *outp,
* which has a pointer to the sigset_t itself followed by a size_t containing
* the sigset size.
*/
struct sigset_argpack {
sigset_t __user *p;
size_t size;
};
static inline int get_sigset_argpack(struct sigset_argpack *to,
struct sigset_argpack __user *from)
{
// the path is hot enough for overhead of copy_from_user() to matter
if (from) {
if (!user_read_access_begin(from, sizeof(*from)))
return -EFAULT;
unsafe_get_user(to->p, &from->p, Efault);
unsafe_get_user(to->size, &from->size, Efault);
user_read_access_end();
}
return 0;
Efault:
user_access_end();
return -EFAULT;
}
SYSCALL_DEFINE6(pselect6, int, n, fd_set __user *, inp, fd_set __user *, outp,
fd_set __user *, exp, struct __kernel_timespec __user *, tsp,
void __user *, sig)
{
size_t sigsetsize = 0;
sigset_t __user *up = NULL;
struct sigset_argpack x = {NULL, 0};
if (sig) {
if (!access_ok(sig, sizeof(void *)+sizeof(size_t))
|| __get_user(up, (sigset_t __user * __user *)sig)
|| __get_user(sigsetsize,
(size_t __user *)(sig+sizeof(void *))))
return -EFAULT;
}
if (get_sigset_argpack(&x, sig))
return -EFAULT;
return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_TIMESPEC);
return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_TIMESPEC);
}
#if defined(CONFIG_COMPAT_32BIT_TIME) && !defined(CONFIG_64BIT)
@ -790,18 +806,12 @@ SYSCALL_DEFINE6(pselect6_time32, int, n, fd_set __user *, inp, fd_set __user *,
fd_set __user *, exp, struct old_timespec32 __user *, tsp,
void __user *, sig)
{
size_t sigsetsize = 0;
sigset_t __user *up = NULL;
struct sigset_argpack x = {NULL, 0};
if (sig) {
if (!access_ok(sig, sizeof(void *)+sizeof(size_t))
|| __get_user(up, (sigset_t __user * __user *)sig)
|| __get_user(sigsetsize,
(size_t __user *)(sig+sizeof(void *))))
return -EFAULT;
}
if (get_sigset_argpack(&x, sig))
return -EFAULT;
return do_pselect(n, inp, outp, exp, tsp, up, sigsetsize, PT_OLD_TIMESPEC);
return do_pselect(n, inp, outp, exp, tsp, x.p, x.size, PT_OLD_TIMESPEC);
}
#endif
@ -1325,24 +1335,37 @@ static long do_compat_pselect(int n, compat_ulong_t __user *inp,
return poll_select_finish(&end_time, tsp, type, ret);
}
struct compat_sigset_argpack {
compat_uptr_t p;
compat_size_t size;
};
static inline int get_compat_sigset_argpack(struct compat_sigset_argpack *to,
struct compat_sigset_argpack __user *from)
{
if (from) {
if (!user_read_access_begin(from, sizeof(*from)))
return -EFAULT;
unsafe_get_user(to->p, &from->p, Efault);
unsafe_get_user(to->size, &from->size, Efault);
user_read_access_end();
}
return 0;
Efault:
user_access_end();
return -EFAULT;
}
COMPAT_SYSCALL_DEFINE6(pselect6_time64, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct __kernel_timespec __user *, tsp, void __user *, sig)
{
compat_size_t sigsetsize = 0;
compat_uptr_t up = 0;
struct compat_sigset_argpack x = {0, 0};
if (sig) {
if (!access_ok(sig,
sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
__get_user(up, (compat_uptr_t __user *)sig) ||
__get_user(sigsetsize,
(compat_size_t __user *)(sig+sizeof(up))))
return -EFAULT;
}
if (get_compat_sigset_argpack(&x, sig))
return -EFAULT;
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
sigsetsize, PT_TIMESPEC);
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p),
x.size, PT_TIMESPEC);
}
#if defined(CONFIG_COMPAT_32BIT_TIME)
@ -1351,20 +1374,13 @@ COMPAT_SYSCALL_DEFINE6(pselect6_time32, int, n, compat_ulong_t __user *, inp,
compat_ulong_t __user *, outp, compat_ulong_t __user *, exp,
struct old_timespec32 __user *, tsp, void __user *, sig)
{
compat_size_t sigsetsize = 0;
compat_uptr_t up = 0;
struct compat_sigset_argpack x = {0, 0};
if (sig) {
if (!access_ok(sig,
sizeof(compat_uptr_t)+sizeof(compat_size_t)) ||
__get_user(up, (compat_uptr_t __user *)sig) ||
__get_user(sigsetsize,
(compat_size_t __user *)(sig+sizeof(up))))
return -EFAULT;
}
if (get_compat_sigset_argpack(&x, sig))
return -EFAULT;
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(up),
sigsetsize, PT_OLD_TIMESPEC);
return do_compat_pselect(n, inp, outp, exp, tsp, compat_ptr(x.p),
x.size, PT_OLD_TIMESPEC);
}
#endif