Initialize potentially uninitialized local variables

Compiling OpenSSL code with MSVC and /W4 results in a number of warnings.
One category of warnings is particularly interesting - C4701 (potentially
uninitialized local variable 'name' used). This warning pretty much means
that there's a code path which results in uninitialized variables being used
or returned. Depending on compiler, its options, OS, values in registers
and/or stack, the results can be nondeterministic. Cases like this are very
hard to debug so it's rational to fix these issues.

This patch contains a set of trivial fixes for all the C4701 warnings (just
initializing variables to 0 or NULL or appropriate error code) to make sure
that deterministic values will be returned from all the execution paths.

RT#3835

Signed-off-by: Matt Caswell <matt@openssl.org>

Matt's note: All of these appear to be bogus warnings, i.e. there isn't
actually a code path where an unitialised variable could be used - its just
that the compiler hasn't been able to figure that out from the logic. So
this commit is just about silencing spurious warnings.

Reviewed-by: Rich Salz <rsalz@openssl.org>

1 files changed, 5 insertions, 5 deletions

diff --git a/crypto/evp/m_sigver.c b/crypto/evp/m_sigver.c
index 65a49adf42..288c563d99 100644
--- a/crypto/evp/m_sigver.c
+++ b/crypto/evp/m_sigver.c
@@ -128,7 +128,7 @@ int EVP_DigestVerifyInit(EVP_MD_CTX *ctx, EVP_PKEY_CTX **pctx,
 int EVP_DigestSignFinal(EVP_MD_CTX *ctx, unsigned char *sigret,
                         size_t *siglen)
 {
-    int sctx, r = 0;
+    int sctx = 0, r = 0;
     EVP_PKEY_CTX *pctx = ctx->pctx;
     if (pctx->pmeth->flags & EVP_PKEY_FLAG_SIGCTX_CUSTOM) {
         if (!sigret)
@@ -150,7 +150,7 @@ int EVP_DigestSignFinal(EVP_MD_CTX *ctx, unsigned char *sigret,
         sctx = 0;
     if (sigret) {
         unsigned char md[EVP_MAX_MD_SIZE];
-        unsigned int mdlen;
+        unsigned int mdlen = 0;
         if (ctx->flags & EVP_MD_CTX_FLAG_FINALISE) {
             if (sctx)
                 r = ctx->pctx->pmeth->signctx(ctx->pctx, sigret, siglen, ctx);
@@ -189,9 +189,9 @@ int EVP_DigestVerifyFinal(EVP_MD_CTX *ctx, const unsigned char *sig,
                           size_t siglen)
 {
     unsigned char md[EVP_MAX_MD_SIZE];
-    int r;
-    unsigned int mdlen;
-    int vctx;
+    int r = 0;
+    unsigned int mdlen = 0;
+    int vctx = 0;
 
     if (ctx->pctx->pmeth->verifyctx)
         vctx = 1;