The 4 tests that I added all fail on the empty file. Example: $ ./test-sha1 sha1_stream produced wrong result. Expected: \xda\x39\xa3\xee\x5e\x6b\x4b\x0d\x32\x55\xbf\xef\x95\x60\x18\x90\xaf\xd8\x07\x09 Got: \x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00
Seen on Ubuntu 16.04 LTS with a kernel version 4.4.0-119, which somewhat corresponds to the kernel.org version 4.4.114 [1]. [1] https://people.canonical.com/~kernel/info/kernel-version-map.html This workaround makes the tests pass: 2018-05-05 Bruno Haible <br...@clisp.org> af_alg: Fix bug on empty files. * lib/af_alg.c (afalg_stream): Ignore the kernel's result if the input stream is empty. diff --git a/lib/af_alg.c b/lib/af_alg.c index 1f4a6aa..06344b1 100644 --- a/lib/af_alg.c +++ b/lib/af_alg.c @@ -83,10 +83,12 @@ afalg_stream (FILE * stream, const char *alg, void *resblock, ssize_t hashlen) else { /* sendfile not possible, do a classic read-write loop. */ + int non_empty = 0; ssize_t size; char buf[BLOCKSIZE]; while ((size = fread (buf, 1, sizeof buf, stream))) { + non_empty = 1; if (send (ofd, buf, size, MSG_MORE) != size) { ret = -EIO; @@ -98,6 +100,13 @@ afalg_stream (FILE * stream, const char *alg, void *resblock, ssize_t hashlen) ret = -EIO; goto out_ofd; } + /* On Linux 4.4.0 at least, the value for an empty stream is wrong + (all zeroes). */ + if (!non_empty) + { + ret = -EAFNOSUPPORT; + goto out_ofd; + } } if (read (ofd, resblock, hashlen) != hashlen)
