[PATCH v3 3/4] perf genelf: Remove libcrypto dependency and use built-in sha1()

[Eric Biggers <ebiggers@kernel.org>]

From: Yuzhuo Jing <yuzhuo@google.com>

genelf is the only file in perf that depends on libcrypto (or openssl)
which only calculates a Build ID (SHA1, MD5, or URANDOM).  SHA1 was
expected to be the default option, but MD5 was used by default due to
previous issues when linking against Java.  This commit switches genelf
to use the in-house sha1(), and also removes MD5 and URANDOM options
since we have a reliable SHA1 implementation to rely on.  It passes the
tools/perf/tests/shell/test_java_symbol.sh test.

Signed-off-by: Yuzhuo Jing <yuzhuo@google.com>
Co-developed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 tools/perf/util/genelf.c | 85 ++--------------------------------------
 1 file changed, 3 insertions(+), 82 deletions(-)

diff --git a/tools/perf/util/genelf.c b/tools/perf/util/genelf.c
index cdce7f173d00a..fcf86a27f69e1 100644
--- a/tools/perf/util/genelf.c
+++ b/tools/perf/util/genelf.c
@@ -10,45 +10,25 @@
 #include <sys/types.h>
 #include <stddef.h>
 #include <libelf.h>
 #include <string.h>
 #include <stdlib.h>
-#include <unistd.h>
 #include <inttypes.h>
-#include <fcntl.h>
 #include <err.h>
 #ifdef HAVE_LIBDW_SUPPORT
 #include <dwarf.h>
 #endif
 
 #include "genelf.h"
+#include "sha1.h"
 #include "../util/jitdump.h"
 #include <linux/compiler.h>
 
 #ifndef NT_GNU_BUILD_ID
 #define NT_GNU_BUILD_ID 3
 #endif
 
-#define BUILD_ID_URANDOM /* different uuid for each run */
-
-#ifdef HAVE_LIBCRYPTO_SUPPORT
-
-#define BUILD_ID_MD5
-#undef BUILD_ID_SHA	/* does not seem to work well when linked with Java */
-#undef BUILD_ID_URANDOM /* different uuid for each run */
-
-#ifdef BUILD_ID_SHA
-#include <openssl/sha.h>
-#endif
-
-#ifdef BUILD_ID_MD5
-#include <openssl/evp.h>
-#include <openssl/md5.h>
-#endif
-#endif
-
-
 typedef struct {
   unsigned int namesz;  /* Size of entry's owner string */
   unsigned int descsz;  /* Size of the note descriptor */
   unsigned int type;    /* Interpretation of the descriptor */
   char         name[0]; /* Start of the name+desc data */
@@ -69,11 +49,11 @@ static char shd_string_table[] = {
 };
 
 static struct buildid_note {
 	Elf_Note desc;		/* descsz: size of build-id, must be multiple of 4 */
 	char	 name[4];	/* GNU\0 */
-	char	 build_id[20];
+	u8	 build_id[SHA1_DIGEST_SIZE];
 } bnote;
 
 static Elf_Sym symtab[]={
 	/* symbol 0 MUST be the undefined symbol */
 	{ .st_name  = 0, /* index in sym_string table */
@@ -90,69 +70,10 @@ static Elf_Sym symtab[]={
 	  .st_other = ELF_ST_VIS(STV_DEFAULT),
 	  .st_size  = 0, /* for now */
 	}
 };
 
-#ifdef BUILD_ID_URANDOM
-static void
-gen_build_id(struct buildid_note *note,
-	     unsigned long load_addr __maybe_unused,
-	     const void *code __maybe_unused,
-	     size_t csize __maybe_unused)
-{
-	int fd;
-	size_t sz = sizeof(note->build_id);
-	ssize_t sret;
-
-	fd = open("/dev/urandom", O_RDONLY);
-	if (fd == -1)
-		err(1, "cannot access /dev/urandom for buildid");
-
-	sret = read(fd, note->build_id, sz);
-
-	close(fd);
-
-	if (sret != (ssize_t)sz)
-		memset(note->build_id, 0, sz);
-}
-#endif
-
-#ifdef BUILD_ID_SHA
-static void
-gen_build_id(struct buildid_note *note,
-	     unsigned long load_addr __maybe_unused,
-	     const void *code,
-	     size_t csize)
-{
-	if (sizeof(note->build_id) < SHA_DIGEST_LENGTH)
-		errx(1, "build_id too small for SHA1");
-
-	SHA1(code, csize, (unsigned char *)note->build_id);
-}
-#endif
-
-#ifdef BUILD_ID_MD5
-static void
-gen_build_id(struct buildid_note *note, unsigned long load_addr, const void *code, size_t csize)
-{
-	EVP_MD_CTX *mdctx;
-
-	if (sizeof(note->build_id) < 16)
-		errx(1, "build_id too small for MD5");
-
-	mdctx = EVP_MD_CTX_new();
-	if (!mdctx)
-		errx(2, "failed to create EVP_MD_CTX");
-
-	EVP_DigestInit_ex(mdctx, EVP_md5(), NULL);
-	EVP_DigestUpdate(mdctx, &load_addr, sizeof(load_addr));
-	EVP_DigestUpdate(mdctx, code, csize);
-	EVP_DigestFinal_ex(mdctx, (unsigned char *)note->build_id, NULL);
-	EVP_MD_CTX_free(mdctx);
-}
-#endif
-
 static int
 jit_add_eh_frame_info(Elf *e, void* unwinding, uint64_t unwinding_header_size,
 		      uint64_t unwinding_size, uint64_t base_offset)
 {
 	Elf_Data *d;
@@ -471,11 +392,11 @@ jit_write_elf(int fd, uint64_t load_addr, const char *sym,
 	}
 
 	/*
 	 * build-id generation
 	 */
-	gen_build_id(&bnote, load_addr, code, csize);
+	sha1(code, csize, bnote.build_id);
 	bnote.desc.namesz = sizeof(bnote.name); /* must include 0 termination */
 	bnote.desc.descsz = sizeof(bnote.build_id);
 	bnote.desc.type   = NT_GNU_BUILD_ID;
 	strcpy(bnote.name, "GNU");
 
-- 
2.50.0