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, 134 insertions, 18 deletions

diff --git a/minzip/SysUtil.c b/minzip/SysUtil.c
index e6f6506..2cfa39a 100644
--- a/minzip/SysUtil.c
+++ b/minzip/SysUtil.c
@@ -8,11 +8,14 @@
 #include <unistd.h>
 #include <string.h>
 #include <sys/mman.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
 #include <limits.h>
 #include <errno.h>
 #include <assert.h>
 
-#define LOG_TAG "minzip"
+#define LOG_TAG "sysutil"
 #include "Log.h"
 #include "SysUtil.h"
 
@@ -46,13 +49,13 @@ static int getFileStartAndLength(int fd, off_t *start_, size_t *length_)
 }
 
 /*
- * Map a file (from fd's current offset) into a shared, read-only memory
+ * Map a file (from fd's current offset) into a private, read-only memory
  * segment.  The file offset must be a multiple of the page size.
  *
  * On success, returns 0 and fills out "pMap".  On failure, returns a nonzero
  * value and does not disturb "pMap".
  */
-int sysMapFileInShmem(int fd, MemMapping* pMap)
+static int sysMapFD(int fd, MemMapping* pMap)
 {
     off_t start;
     size_t length;
@@ -63,33 +66,146 @@ int sysMapFileInShmem(int fd, MemMapping* pMap)
     if (getFileStartAndLength(fd, &start, &length) < 0)
         return -1;
 
-    memPtr = mmap(NULL, length, PROT_READ, MAP_FILE | MAP_SHARED, fd, start);
+    memPtr = mmap(NULL, length, PROT_READ, MAP_PRIVATE, fd, start);
     if (memPtr == MAP_FAILED) {
-        LOGW("mmap(%d, R, FILE|SHARED, %d, %d) failed: %s\n", (int) length,
+        LOGW("mmap(%d, R, PRIVATE, %d, %d) failed: %s\n", (int) length,
             fd, (int) start, strerror(errno));
         return -1;
     }
 
-    pMap->baseAddr = pMap->addr = memPtr;
-    pMap->baseLength = pMap->length = length;
+    pMap->addr = memPtr;
+    pMap->length = length;
+    pMap->range_count = 1;
+    pMap->ranges = malloc(sizeof(MappedRange));
+    pMap->ranges[0].addr = memPtr;
+    pMap->ranges[0].length = length;
 
     return 0;
 }
 
+static int sysMapBlockFile(FILE* mapf, MemMapping* pMap)
+{
+    char block_dev[PATH_MAX+1];
+    size_t size;
+    unsigned int blksize;
+    unsigned int blocks;
+    unsigned int range_count;
+    unsigned int i;
+
+    if (fgets(block_dev, sizeof(block_dev), mapf) == NULL) {
+        LOGW("failed to read block device from header\n");
+        return -1;
+    }
+    for (i = 0; i < sizeof(block_dev); ++i) {
+        if (block_dev[i] == '\n') {
+            block_dev[i] = 0;
+            break;
+        }
+    }
+
+    if (fscanf(mapf, "%d %d\n%d\n", &size, &blksize, &range_count) != 3) {
+        LOGW("failed to parse block map header\n");
+        return -1;
+    }
+
+    blocks = ((size-1) / blksize) + 1;
+
+    pMap->range_count = range_count;
+    pMap->ranges = malloc(range_count * sizeof(MappedRange));
+    memset(pMap->ranges, 0, range_count * sizeof(MappedRange));
+
+    // Reserve enough contiguous address space for the whole file.
+    unsigned char* reserve;
+    reserve = mmap64(NULL, blocks * blksize, PROT_NONE, MAP_PRIVATE | MAP_ANON, -1, 0);
+    if (reserve == MAP_FAILED) {
+        LOGW("failed to reserve address space: %s\n", strerror(errno));
+        return -1;
+    }
+
+    pMap->ranges[range_count-1].addr = reserve;
+    pMap->ranges[range_count-1].length = blocks * blksize;
+
+    int fd = open(block_dev, O_RDONLY);
+    if (fd < 0) {
+        LOGW("failed to open block device %s: %s\n", block_dev, strerror(errno));
+        return -1;
+    }
+
+    unsigned char* next = reserve;
+    for (i = 0; i < range_count; ++i) {
+        int start, end;
+        if (fscanf(mapf, "%d %d\n", &start, &end) != 2) {
+            LOGW("failed to parse range %d in block map\n", i);
+            return -1;
+        }
+
+        void* addr = mmap64(next, (end-start)*blksize, PROT_READ, MAP_PRIVATE | MAP_FIXED, fd, ((off64_t)start)*blksize);
+        if (addr == MAP_FAILED) {
+            LOGW("failed to map block %d: %s\n", i, strerror(errno));
+            return -1;
+        }
+        pMap->ranges[i].addr = addr;
+        pMap->ranges[i].length = (end-start)*blksize;
+
+        next += pMap->ranges[i].length;
+    }
+
+    pMap->addr = reserve;
+    pMap->length = size;
+
+    return 0;
+}
+
+int sysMapFile(const char* fn, MemMapping* pMap)
+{
+    memset(pMap, 0, sizeof(*pMap));
+
+    if (fn && fn[0] == '@') {
+        // A map of blocks
+        FILE* mapf = fopen(fn+1, "r");
+        if (mapf == NULL) {
+            LOGV("Unable to open '%s': %s\n", fn+1, strerror(errno));
+            return -1;
+        }
+
+        if (sysMapBlockFile(mapf, pMap) != 0) {
+            LOGW("Map of '%s' failed\n", fn);
+            return -1;
+        }
+
+        fclose(mapf);
+    } else {
+        // This is a regular file.
+        int fd = open(fn, O_RDONLY, 0);
+        if (fd < 0) {
+            LOGE("Unable to open '%s': %s\n", fn, strerror(errno));
+            return -1;
+        }
+
+        if (sysMapFD(fd, pMap) != 0) {
+            LOGE("Map of '%s' failed\n", fn);
+            close(fd);
+            return -1;
+        }
+
+        close(fd);
+    }
+    return 0;
+}
+
 /*
  * Release a memory mapping.
  */
-void sysReleaseShmem(MemMapping* pMap)
+void sysReleaseMap(MemMapping* pMap)
 {
-    if (pMap->baseAddr == NULL && pMap->baseLength == 0)
-        return;
-
-    if (munmap(pMap->baseAddr, pMap->baseLength) < 0) {
-        LOGW("munmap(%p, %d) failed: %s\n",
-            pMap->baseAddr, (int)pMap->baseLength, strerror(errno));
-    } else {
-        LOGV("munmap(%p, %d) succeeded\n", pMap->baseAddr, pMap->baseLength);
-        pMap->baseAddr = NULL;
-        pMap->baseLength = 0;
+    int i;
+    for (i = 0; i < pMap->range_count; ++i) {
+        if (munmap(pMap->ranges[i].addr, pMap->ranges[i].length) < 0) {
+            LOGW("munmap(%p, %d) failed: %s\n",
+                 pMap->ranges[i].addr, (int)pMap->ranges[i].length, strerror(errno));
+        }
     }
+    free(pMap->ranges);
+    pMap->ranges = NULL;
+    pMap->range_count = 0;
 }