evp: prevent underflow in base64 decoding

[openssl.git] / crypto / evp / encode.c

diff --git a/crypto/evp/encode.c b/crypto/evp/encode.c
index 5921f0d710d8faed65c203cf180a7a4b320facb8..4654bdc61a64838353562a57ec85e14a623fdfa2 100644 (file)
--- a/crypto/evp/encode.c
+++ b/crypto/evp/encode.c
@@ -85,7 +85,7 @@
 #define CHUNKS_PER_LINE (64/4)
 #define CHAR_PER_LINE   (64+1)
 
-static unsigned char data_bin2ascii[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZ\
+static const unsigned char data_bin2ascii[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZ\
 abcdefghijklmnopqrstuvwxyz0123456789+/";
 
 /* 0xF0 is a EOLN
@@ -102,7 +102,7 @@ abcdefghijklmnopqrstuvwxyz0123456789+/";
 #define B64_ERROR              0xFF
 #define B64_NOT_BASE64(a)      (((a)|0x13) == 0xF3)
 
-static unsigned char data_ascii2bin[128]={
+static const unsigned char data_ascii2bin[128]={
        0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
        0xFF,0xE0,0xF0,0xFF,0xFF,0xF1,0xFF,0xFF,
        0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,0xFF,
@@ -235,7 +235,7 @@ void EVP_DecodeInit(EVP_ENCODE_CTX *ctx)
 int EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl,
             const unsigned char *in, int inl)
        {
-       int seof= -1,eof=0,rv= -1,ret=0,i,v,tmp,n,ln,tmp2,exp_nl;
+       int seof= -1,eof=0,rv= -1,ret=0,i,v,tmp,n,ln,exp_nl;
        unsigned char *d;
 
        n=ctx->num;
@@ -319,12 +319,12 @@ int EVP_DecodeUpdate(EVP_ENCODE_CTX *ctx, unsigned char *out, int *outl,
                         * lines.  We process the line and then need to
                         * accept the '\n' */
                        if ((v != B64_EOF) && (n >= 64)) exp_nl=1;
-                       tmp2=v;
                        if (n > 0)
                                {
                                v=EVP_DecodeBlock(out,d,n);
                                n=0;
                                if (v < 0) { rv=0; goto end; }
+                               if (eof > v) { rv=-1; goto end; }
                                ret+=(v-eof);
                                }
                        else