From 644478e8db56f305601c3628a74e53de048b28c8 Mon Sep 17 00:00:00 2001 From: David Kalnischkies Date: Wed, 31 Aug 2016 10:11:07 +0200 Subject: try not to call memcpy with length 0 in hash calculations memcpy is marked as nonnull for its input, but ignores the input anyhow if the declared length is zero. Our SHA2 implementations do this as well, it was "just" MD5 and SHA1 missing, so we add the length check here as well as along the callstack as it is really pointless to do all these method calls for "nothing". Reported-By: gcc -fsanitize=undefined --- methods/rred.cc | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'methods') diff --git a/methods/rred.cc b/methods/rred.cc index 0c641ad82..958933a07 100644 --- a/methods/rred.cc +++ b/methods/rred.cc @@ -335,7 +335,7 @@ class Patch { FileChanges filechanges; MemBlock add_text; - static bool retry_fwrite(char *b, size_t l, FileFd &f, Hashes * const start_hash, Hashes * const end_hash = nullptr) + static bool retry_fwrite(char *b, size_t l, FileFd &f, Hashes * const start_hash, Hashes * const end_hash = nullptr) APT_NONNULL(1) { if (f.Write(b, l) == false) return false; @@ -385,8 +385,8 @@ class Patch { } } - static void dump_mem(FileFd &o, char *p, size_t s, Hashes *hash) { - retry_fwrite(p, s, o, hash); + static void dump_mem(FileFd &o, char *p, size_t s, Hashes *hash) APT_NONNULL(2) { + retry_fwrite(p, s, o, nullptr, hash); } public: @@ -538,7 +538,8 @@ class Patch { for (ch = filechanges.begin(); ch != filechanges.end(); ++ch) { dump_lines(out, in, ch->offset, start_hash, end_hash); skip_lines(in, ch->del_cnt, start_hash); - dump_mem(out, ch->add, ch->add_len, end_hash); + if (ch->add_len != 0) + dump_mem(out, ch->add, ch->add_len, end_hash); } dump_rest(out, in, start_hash, end_hash); out.Flush(); -- cgit v1.2.3