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[PATCH 3/4] semihosting: Check for errors on SET_ARG()
From: |
Peter Maydell |
Subject: |
[PATCH 3/4] semihosting: Check for errors on SET_ARG() |
Date: |
Tue, 19 Jul 2022 13:11:09 +0100 |
The SET_ARG() macro returns an error indication; we check this in the
TARGET_SYS_GET_CMDLINE case but not when we use it in implementing
TARGET_SYS_ELAPSED. Check for and handle the errors via the do_fault
codepath, and update the comment documenting the SET_ARG() and
GET_ARG() macros to note how they handle memory access errors.
Resolves: Coverity CID 1490287
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
semihosting/arm-compat-semi.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/semihosting/arm-compat-semi.c b/semihosting/arm-compat-semi.c
index 1a1e2a69605..d12288fc806 100644
--- a/semihosting/arm-compat-semi.c
+++ b/semihosting/arm-compat-semi.c
@@ -171,6 +171,12 @@ static LayoutInfo common_semi_find_bases(CPUState *cs)
* Read the input value from the argument block; fail the semihosting
* call if the memory read fails. Eventually we could use a generic
* CPUState helper function here.
+ * Note that GET_ARG() handles memory access errors by jumping to
+ * do_fault, so must be used as the first thing done in handling a
+ * semihosting call, to avoid accidentally leaking allocated resources.
+ * SET_ARG(), since it unavoidably happens late, instead returns an
+ * error indication (0 on success, non-0 for error) which the caller
+ * should check.
*/
#define GET_ARG(n) do { \
@@ -739,10 +745,14 @@ void do_common_semihosting(CPUState *cs)
case TARGET_SYS_ELAPSED:
elapsed = get_clock() - clock_start;
if (sizeof(target_ulong) == 8) {
- SET_ARG(0, elapsed);
+ if (SET_ARG(0, elapsed)) {
+ goto do_fault;
+ }
} else {
- SET_ARG(0, (uint32_t) elapsed);
- SET_ARG(1, (uint32_t) (elapsed >> 32));
+ if (SET_ARG(0, (uint32_t) elapsed) ||
+ SET_ARG(1, (uint32_t) (elapsed >> 32))) {
+ goto do_fault;
+ }
}
common_semi_set_ret(cs, 0);
break;
--
2.25.1