Author: andrew
Date: Wed Sep 9 11:51:14 2015
New Revision: 287596
URL: https://svnweb.freebsd.org/changeset/base/287596
Log:
Rework copyinstr to:
* Fail when the length passed in is 0
* Remove an unneeded increment of the count on success
* Return ENAMETOOLONG when the input pointer is too long
Sponsored by: ABT Systems Ltd
Modified:
head/sys/arm64/arm64/copyinout.S
Modified: head/sys/arm64/arm64/copyinout.S
==============================================================================
--- head/sys/arm64/arm64/copyinout.S Wed Sep 9 09:19:07 2015
(r287595)
+++ head/sys/arm64/arm64/copyinout.S Wed Sep 9 11:51:14 2015
(r287596)
@@ -95,6 +95,7 @@ END(copyin)
*/
ENTRY(copyinstr)
mov x5, xzr /* count = 0 */
+ mov w4, #1 /* If zero return faulure */
cbz x2, 3f /* If len == 0 then skip loop */
adr x6, copyio_fault /* Get the handler address */
@@ -102,17 +103,18 @@ ENTRY(copyinstr)
1: ldrb w4, [x0], #1 /* Load from uaddr */
strb w4, [x1], #1 /* Store in kaddr */
- cbz w4, 2f /* If == 0 then break */
- sub x2, x2, #1 /* len-- */
add x5, x5, #1 /* count++ */
+ cbz w4, 2f /* Break when NUL-terminated */
+ sub x2, x2, #1 /* len-- */
cbnz x2, 1b
2: SET_FAULT_HANDLER(xzr, x7) /* Clear the handler */
3: cbz x3, 4f /* Check if done != NULL */
- add x5, x5, #1 /* count++ */
str x5, [x3] /* done = count */
-4: mov x0, xzr /* return 0 */
+4: mov w1, #ENAMETOOLONG /* Load ENAMETOOLONG to return if failed */
+ cmp w4, #0 /* Check if we saved the NUL-terminator */
+ csel w0, wzr, w1, eq /* If so return success, else failure */
ret
END(copyinstr)
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