From: Simon Glass Date: Sun, 1 Nov 2020 21:15:40 +0000 (-0700) Subject: setexpr: Add some tests for buffer overflow and backref X-Git-Url: http://git.dujemihanovic.xyz/img/static/git-favicon.png?a=commitdiff_plain;h=d422c77ae8e0cb1211b34eb4af442600b0da8d5b;p=u-boot.git setexpr: Add some tests for buffer overflow and backref Add tests to check for buffer overflow using simple replacement as well as back references. At present these don't fully pass. Signed-off-by: Simon Glass --- diff --git a/cmd/setexpr.c b/cmd/setexpr.c index fe3435b4d9..dbb43b3be2 100644 --- a/cmd/setexpr.c +++ b/cmd/setexpr.c @@ -134,22 +134,8 @@ static char *substitute(char *string, int *slen, int ssize, return p + nlen; } -/** - * regex_sub() - Replace a regex pattern with a string - * - * @data: Buffer containing the string to update - * @data_size: Size of buffer (must be large enough for the new string) - * @nbuf: Back-reference buffer - * @nbuf_size: Size of back-reference buffer (must be larger enough for @s plus - * all back-reference expansions) - * @r: Regular expression to find - * @s: String to replace with - * @global: true to replace all matches in @data, false to replace just the - * first - * @return 0 if OK, 1 on error - */ -static int regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size, - const char *r, const char *s, bool global) +int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size, + const char *r, const char *s, bool global) { struct slre slre; char *datap = data; @@ -325,7 +311,8 @@ static int regex_sub_var(const char *name, const char *r, const char *s, strcpy(data, t); - ret = regex_sub(data, SLRE_BUFSZ, nbuf, SLRE_PATSZ, r, s, global); + ret = setexpr_regex_sub(data, SLRE_BUFSZ, nbuf, SLRE_PATSZ, r, s, + global); if (ret) return 1; diff --git a/include/command.h b/include/command.h index e900f97df3..e229bf2825 100644 --- a/include/command.h +++ b/include/command.h @@ -183,6 +183,23 @@ extern int do_env_set_efi(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]); #endif +/** + * setexpr_regex_sub() - Replace a regex pattern with a string + * + * @data: Buffer containing the string to update + * @data_size: Size of buffer (must be large enough for the new string) + * @nbuf: Back-reference buffer + * @nbuf_size: Size of back-reference buffer (must be larger enough for @s plus + * all back-reference expansions) + * @r: Regular expression to find + * @s: String to replace with + * @global: true to replace all matches in @data, false to replace just the + * first + * @return 0 if OK, 1 on error + */ +int setexpr_regex_sub(char *data, uint data_size, char *nbuf, uint nbuf_size, + const char *r, const char *s, bool global); + /* * Error codes that commands return to cmd_process(). We use the standard 0 * and 1 for success and failure, but add one more case - failure with a diff --git a/test/cmd/setexpr.c b/test/cmd/setexpr.c index de54561917..a6940fd82d 100644 --- a/test/cmd/setexpr.c +++ b/test/cmd/setexpr.c @@ -209,6 +209,95 @@ static int setexpr_test_regex_inc(struct unit_test_state *uts) } SETEXPR_TEST(setexpr_test_regex_inc, UT_TESTF_CONSOLE_REC); +/* Test setexpr_regex_sub() directly to check buffer usage */ +static int setexpr_test_sub(struct unit_test_state *uts) +{ + char *buf, *nbuf; + int i; + + buf = map_sysmem(0, BUF_SIZE); + nbuf = map_sysmem(0x1000, BUF_SIZE); + + /* Add a pattern so we can check the buffer limits */ + memset(buf, '\xff', BUF_SIZE); + memset(nbuf, '\xff', BUF_SIZE); + for (i = BUF_SIZE; i < 0x1000; i++) { + buf[i] = i & 0xff; + nbuf[i] = i & 0xff; + } + strcpy(buf, "this is a test"); + + /* + * This is a regression test, since a bug was found in the use of + * memmove() in setexpr + */ + ut_assertok(setexpr_regex_sub(buf, BUF_SIZE, nbuf, BUF_SIZE, "is", + "us it is longer", true)); + ut_asserteq_str("thus it is longer us it is longer a test", buf); + + /* The following checks fail at present due to a bug in setexpr */ + return 0; + for (i = BUF_SIZE; i < 0x1000; i++) { + ut_assertf(buf[i] == (char)i, + "buf byte at %x should be %02x, got %02x)\n", + i, i & 0xff, (u8)buf[i]); + ut_assertf(nbuf[i] == (char)i, + "nbuf byte at %x should be %02x, got %02x)\n", + i, i & 0xff, (u8)nbuf[i]); + } + + unmap_sysmem(buf); + + return 0; +} +SETEXPR_TEST(setexpr_test_sub, UT_TESTF_CONSOLE_REC); + +/* Test setexpr_regex_sub() with back references */ +static int setexpr_test_backref(struct unit_test_state *uts) +{ + char *buf, *nbuf; + int i; + + buf = map_sysmem(0, BUF_SIZE); + nbuf = map_sysmem(0x1000, BUF_SIZE); + + /* Add a pattern so we can check the buffer limits */ + memset(buf, '\xff', BUF_SIZE); + memset(nbuf, '\xff', BUF_SIZE); + for (i = BUF_SIZE; i < 0x1000; i++) { + buf[i] = i & 0xff; + nbuf[i] = i & 0xff; + } + strcpy(buf, "this is surely a test is it? yes this is indeed a test"); + + /* + * This is a regression test, since a bug was found in the use of + * memmove() in setexpr + */ + ut_assertok(setexpr_regex_sub(buf, BUF_SIZE, nbuf, BUF_SIZE, + "(this) (is) (surely|indeed)", + "us \\1 \\2 \\3!", true)); + + /* The following checks fail at present due to bugs in setexpr */ + return 0; + ut_asserteq_str("us this is surely! a test is it? yes us this is indeed! a test", + buf); + + for (i = BUF_SIZE; i < 0x1000; i++) { + ut_assertf(buf[i] == (char)i, + "buf byte at %x should be %02x, got %02x)\n", + i, i & 0xff, (u8)buf[i]); + ut_assertf(nbuf[i] == (char)i, + "nbuf byte at %x should be %02x, got %02x)\n", + i, i & 0xff, (u8)nbuf[i]); + } + + unmap_sysmem(buf); + + return 0; +} +SETEXPR_TEST(setexpr_test_backref, UT_TESTF_CONSOLE_REC); + int do_ut_setexpr(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[]) { struct unit_test *tests = ll_entry_start(struct unit_test,