[PATCH 4.19 247/267] sparc64: fix misuses of access_process_vm() in genregs32_[sg]et()

Greg Kroah-Hartman
2020-06-19T16:15:02Z

From: Al Viro <viro@zeniv.linux.org.uk>

commit 142cd25293f6a7ecbdff4fb0af17de6438d46433 upstream.

We do need access_process_vm() to access the target's reg_window.
However, access to caller's memory (storing the result in
genregs32_get(), fetching the new values in case of genregs32_set())
should be done by normal uaccess primitives.

Fixes: ad4f95764040 ([SPARC64]: Fix user accesses in regset code.)
Cc: stable@kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/sparc/kernel/ptrace_64.c | 17 +++--------------
1 file changed, 3 insertions(+), 14 deletions(-)

--- a/arch/sparc/kernel/ptrace_64.c
+++ b/arch/sparc/kernel/ptrace_64.c
@@ -571,19 +571,13 @@ static int genregs32_get(struct task_str
for (; count > 0 && pos < 32; count--) {
if (access_process_vm(target,
(unsigned long)
- &reg_window[pos],
+ &reg_window[pos++],
&reg, sizeof(reg),
FOLL_FORCE)
!= sizeof(reg))
return -EFAULT;
- if (access_process_vm(target,
- (unsigned long) u,
- &reg, sizeof(reg),
- FOLL_FORCE | FOLL_WRITE)
- != sizeof(reg))
+ if (put_user(reg, u++))
return -EFAULT;
- pos++;
- u++;
}
}
}
@@ -683,12 +677,7 @@ static int genregs32_set(struct task_str
}
} else {
for (; count > 0 && pos < 32; count--) {
- if (access_process_vm(target,
- (unsigned long)
- u,
- &reg, sizeof(reg),
- FOLL_FORCE)
- != sizeof(reg))
+ if (get_user(reg, u++))
return -EFAULT;
if (access_process_vm(target,
(unsigned long)