do verification and extraction on memory, not files

Changes minzip and recovery's file signature verification to work on
memory regions, rather than files.

For packages which are regular files, install.cpp now mmap()s them
into memory and then passes the mapped memory to the verifier and to
the minzip library.

Support for files which are raw block maps (which will be used when we
have packages written to encrypted data partitions) is present but
largely untested so far.

Bug: 12188746
Change-Id: I12cc3e809834745a489dd9d4ceb558cbccdc3f71

1 files changed, 15 insertions, 55 deletions

diff --git a/verifier.cpp b/verifier.cpp
index 0930fbd..55d58ee 100644
--- a/verifier.cpp
+++ b/verifier.cpp
@@ -111,15 +111,10 @@ static bool read_pkcs7(uint8_t* pkcs7_der, size_t pkcs7_der_len, uint8_t** sig_d
 // Return VERIFY_SUCCESS, VERIFY_FAILURE (if any error is encountered
 // or no key matches the signature).
 
-int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys) {
+int verify_file(unsigned char* addr, size_t length,
+                const Certificate* pKeys, unsigned int numKeys) {
     ui->SetProgress(0.0);
 
-    FILE* f = fopen(path, "rb");
-    if (f == NULL) {
-        LOGE("failed to open %s (%s)\n", path, strerror(errno));
-        return VERIFY_FAILURE;
-    }
-
     // An archive with a whole-file signature will end in six bytes:
     //
     //   (2-byte signature start) $ff $ff (2-byte comment size)
@@ -131,22 +126,15 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
 
 #define FOOTER_SIZE 6
 
-    if (fseek(f, -FOOTER_SIZE, SEEK_END) != 0) {
-        LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
-        fclose(f);
+    if (length < FOOTER_SIZE) {
+        LOGE("not big enough to contain footer\n");
         return VERIFY_FAILURE;
     }
 
-    unsigned char footer[FOOTER_SIZE];
-    if (fread(footer, 1, FOOTER_SIZE, f) != FOOTER_SIZE) {
-        LOGE("failed to read footer from %s (%s)\n", path, strerror(errno));
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
+    unsigned char* footer = addr + length - FOOTER_SIZE;
 
     if (footer[2] != 0xff || footer[3] != 0xff) {
         LOGE("footer is wrong\n");
-        fclose(f);
         return VERIFY_FAILURE;
     }
 
@@ -157,7 +145,6 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
 
     if (signature_start <= FOOTER_SIZE) {
         LOGE("Signature start is in the footer");
-        fclose(f);
         return VERIFY_FAILURE;
     }
 
@@ -167,9 +154,8 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     // comment length.
     size_t eocd_size = comment_size + EOCD_HEADER_SIZE;
 
-    if (fseek(f, -eocd_size, SEEK_END) != 0) {
-        LOGE("failed to seek in %s (%s)\n", path, strerror(errno));
-        fclose(f);
+    if (length < eocd_size) {
+        LOGE("not big enough to contain EOCD\n");
         return VERIFY_FAILURE;
     }
 
@@ -177,26 +163,15 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     // This is everything except the signature data and length, which
     // includes all of the EOCD except for the comment length field (2
     // bytes) and the comment data.
-    size_t signed_len = ftell(f) + EOCD_HEADER_SIZE - 2;
+    size_t signed_len = length - eocd_size + EOCD_HEADER_SIZE - 2;
 
-    unsigned char* eocd = (unsigned char*)malloc(eocd_size);
-    if (eocd == NULL) {
-        LOGE("malloc for EOCD record failed\n");
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
-    if (fread(eocd, 1, eocd_size, f) != eocd_size) {
-        LOGE("failed to read eocd from %s (%s)\n", path, strerror(errno));
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
+    unsigned char* eocd = addr + length - eocd_size;
 
     // If this is really is the EOCD record, it will begin with the
     // magic number $50 $4b $05 $06.
     if (eocd[0] != 0x50 || eocd[1] != 0x4b ||
         eocd[2] != 0x05 || eocd[3] != 0x06) {
         LOGE("signature length doesn't match EOCD marker\n");
-        fclose(f);
         return VERIFY_FAILURE;
     }
 
@@ -209,7 +184,6 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
             // which could be exploitable.  Fail verification if
             // this sequence occurs anywhere after the real one.
             LOGE("EOCD marker occurs after start of EOCD\n");
-            fclose(f);
             return VERIFY_FAILURE;
         }
     }
@@ -229,35 +203,23 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     SHA256_CTX sha256_ctx;
     SHA_init(&sha1_ctx);
     SHA256_init(&sha256_ctx);
-    unsigned char* buffer = (unsigned char*)malloc(BUFFER_SIZE);
-    if (buffer == NULL) {
-        LOGE("failed to alloc memory for sha1 buffer\n");
-        fclose(f);
-        return VERIFY_FAILURE;
-    }
 
     double frac = -1.0;
     size_t so_far = 0;
-    fseek(f, 0, SEEK_SET);
     while (so_far < signed_len) {
-        size_t size = BUFFER_SIZE;
-        if (signed_len - so_far < size) size = signed_len - so_far;
-        if (fread(buffer, 1, size, f) != size) {
-            LOGE("failed to read data from %s (%s)\n", path, strerror(errno));
-            fclose(f);
-            return VERIFY_FAILURE;
-        }
-        if (need_sha1) SHA_update(&sha1_ctx, buffer, size);
-        if (need_sha256) SHA256_update(&sha256_ctx, buffer, size);
+        size_t size = signed_len - so_far;
+        if (size > BUFFER_SIZE) size = BUFFER_SIZE;
+
+        if (need_sha1) SHA_update(&sha1_ctx, addr + so_far, size);
+        if (need_sha256) SHA256_update(&sha256_ctx, addr + so_far, size);
         so_far += size;
+
         double f = so_far / (double)signed_len;
         if (f > frac + 0.02 || size == so_far) {
             ui->SetProgress(f);
             frac = f;
         }
     }
-    fclose(f);
-    free(buffer);
 
     const uint8_t* sha1 = SHA_final(&sha1_ctx);
     const uint8_t* sha256 = SHA256_final(&sha256_ctx);
@@ -269,10 +231,8 @@ int verify_file(const char* path, const Certificate* pKeys, unsigned int numKeys
     if (!read_pkcs7(eocd + eocd_size - signature_start, signature_size, &sig_der,
             &sig_der_length)) {
         LOGE("Could not find signature DER block\n");
-        free(eocd);
         return VERIFY_FAILURE;
     }
-    free(eocd);
 
     /*
      * Check to make sure at least one of the keys matches the signature. Since