fastboot: fix --disable-verifiation error message
There is an unclear error message if we run
`fastboot --disable-verification flash boot boot.img` on a
AVB-disabled device without a /vbmeta partition.
Error message:
terminating with uncaught exception of type std::out_of_range: basic_string
Aborted
This is because the buf->fd of the loaded boot.img is not reset,
before returning from function copy_boot_avb_footer().
Also reset some changes in copy_boot_avb_footer() from commit
If83f785e235569ee8ef0de2b37f11dbd2a9a71f4, to prevent the
unnecessary read of the boot vbmeta if no need to copy the
boot image avb footer.
Bug: 191903922
Test: `fastboot --disable-verification flash boot boot.img` on a device
without /vbmeta and without setting BOARD_AVB_ENABLE to true.
Change-Id: If84f08f1b2e12c4c6ded5cafda2bd1d30e75c662
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index c87ce60..532b524 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -941,7 +941,8 @@
// Tries to locate top-level vbmeta from boot.img footer.
uint64_t footer_offset = buf->sz - AVB_FOOTER_SIZE;
if (0 != data.compare(footer_offset, AVB_FOOTER_MAGIC_LEN, AVB_FOOTER_MAGIC)) {
- die("Failed to find AVB_FOOTER at offset: %" PRId64, footer_offset);
+ die("Failed to find AVB_FOOTER at offset: %" PRId64 ", is BOARD_AVB_ENABLE true?",
+ footer_offset);
}
const AvbFooter* footer = reinterpret_cast<const AvbFooter*>(data.c_str() + footer_offset);
vbmeta_offset = be64toh(footer->vbmeta_offset);
@@ -1021,6 +1022,24 @@
return;
}
+ // If overflows and negative, it should be < buf->sz.
+ int64_t partition_size = static_cast<int64_t>(get_partition_size(partition));
+
+ if (partition_size == buf->sz) {
+ return;
+ }
+ // Some device bootloaders might not implement `fastboot getvar partition-size:boot[_a|_b]`.
+ // In this case, partition_size will be zero.
+ if (partition_size < buf->sz) {
+ fprintf(stderr,
+ "Warning: skip copying boot image avb footer"
+ " (boot partition size: %" PRId64 ", boot image size: %" PRId64 ").\n",
+ partition_size, buf->sz);
+ return;
+ }
+
+ // IMPORTANT: after the following read, we need to reset buf->fd before return (if not die).
+ // Because buf->fd will still be used afterwards.
std::string data;
if (!android::base::ReadFdToString(buf->fd, &data)) {
die("Failed reading from boot");
@@ -1028,17 +1047,9 @@
uint64_t footer_offset = buf->sz - AVB_FOOTER_SIZE;
if (0 != data.compare(footer_offset, AVB_FOOTER_MAGIC_LEN, AVB_FOOTER_MAGIC)) {
+ lseek(buf->fd.get(), 0, SEEK_SET); // IMPORTANT: resets buf->fd before return.
return;
}
- // If overflows and negative, it should be < buf->sz.
- int64_t partition_size = static_cast<int64_t>(get_partition_size(partition));
-
- if (partition_size == buf->sz) {
- return;
- }
- if (partition_size < buf->sz) {
- die("boot partition is smaller than boot image");
- }
unique_fd fd(make_temporary_fd("boot rewriting"));
if (!android::base::WriteStringToFd(data, fd)) {