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The raw index buffer content is not guaranteed to be aligned

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* Ensure alignment by copying the content into a structure on the stack
This commit is contained in:
Jacques Germishuys 2014-09-25 13:07:36 +02:00
parent ad8c8d9325
commit ff97778a7a
1 changed files with 29 additions and 24 deletions
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53
src/index.c
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@ -1767,35 +1767,42 @@ static size_t read_entry(
git_index_entry **out, const void *buffer, size_t buffer_size) git_index_entry **out, const void *buffer, size_t buffer_size)
{ {
size_t path_length, entry_size; size_t path_length, entry_size;
uint16_t flags_raw;
const char *path_ptr; const char *path_ptr;
const struct entry_short *source = buffer; struct entry_short source;
git_index_entry entry = {{0}}; git_index_entry entry = {{0}};
if (INDEX_FOOTER_SIZE + minimal_entry_size > buffer_size) if (INDEX_FOOTER_SIZE + minimal_entry_size > buffer_size)
return 0; return 0;
entry.ctime.seconds = (git_time_t)ntohl(source->ctime.seconds); /* buffer is not guaranteed to be aligned */
entry.ctime.nanoseconds = ntohl(source->ctime.nanoseconds); memcpy(&source, buffer, sizeof(struct entry_short));
entry.mtime.seconds = (git_time_t)ntohl(source->mtime.seconds);
entry.mtime.nanoseconds = ntohl(source->mtime.nanoseconds); entry.ctime.seconds = (git_time_t)ntohl(source.ctime.seconds);
entry.dev = ntohl(source->dev); entry.ctime.nanoseconds = ntohl(source.ctime.nanoseconds);
entry.ino = ntohl(source->ino); entry.mtime.seconds = (git_time_t)ntohl(source.mtime.seconds);
entry.mode = ntohl(source->mode); entry.mtime.nanoseconds = ntohl(source.mtime.nanoseconds);
entry.uid = ntohl(source->uid); entry.dev = ntohl(source.dev);
entry.gid = ntohl(source->gid); entry.ino = ntohl(source.ino);
entry.file_size = ntohl(source->file_size); entry.mode = ntohl(source.mode);
git_oid_cpy(&entry.id, &source->oid); entry.uid = ntohl(source.uid);
entry.flags = ntohs(source->flags); entry.gid = ntohl(source.gid);
entry.file_size = ntohl(source.file_size);
git_oid_cpy(&entry.id, &source.oid);
entry.flags = ntohs(source.flags);
if (entry.flags & GIT_IDXENTRY_EXTENDED) { if (entry.flags & GIT_IDXENTRY_EXTENDED) {
const struct entry_long *source_l = (const struct entry_long *)source; uint16_t flags_raw;
path_ptr = source_l->path; size_t flags_offset;
flags_raw = ntohs(source_l->flags_extended); flags_offset = offsetof(struct entry_long, flags_extended);
memcpy(&entry.flags_extended, &flags_raw, 2); memcpy(&flags_raw, (const char *) buffer + flags_offset,
sizeof(flags_raw));
flags_raw = ntohs(flags_raw);
memcpy(&entry.flags_extended, &flags_raw, sizeof(flags_raw));
path_ptr = (const char *) buffer + offsetof(struct entry_long, path);
} else } else
path_ptr = source->path; path_ptr = (const char *) buffer + offsetof(struct entry_short, path);
path_length = entry.flags & GIT_IDXENTRY_NAMEMASK; path_length = entry.flags & GIT_IDXENTRY_NAMEMASK;
@ -1846,14 +1853,12 @@ static int read_header(struct index_header *dest, const void *buffer)
static size_t read_extension(git_index *index, const char *buffer, size_t buffer_size) static size_t read_extension(git_index *index, const char *buffer, size_t buffer_size)
{ {
const struct index_extension *source;
struct index_extension dest; struct index_extension dest;
size_t total_size; size_t total_size;
source = (const struct index_extension *)(buffer); /* buffer is not guaranteed to be aligned */
memcpy(&dest, buffer, sizeof(struct index_extension));
memcpy(dest.signature, source->signature, 4); dest.extension_size = ntohl(dest.extension_size);
dest.extension_size = ntohl(source->extension_size);
total_size = dest.extension_size + sizeof(struct index_extension); total_size = dest.extension_size + sizeof(struct index_extension);