{"thread":{"id":"11473","subject":"[PATCH] Don't access line[-1] for a zero-length \"line\" from fgets.","startedAt":"2008-01-04T17:37:41Z","lastAt":"2008-01-04T17:37:41Z","messageCount":1,"participants":["Jim Meyering"],"isPatch":true,"patchVersion":1,"patchTotal":null},"messages":[{"id":"64446","messageId":"87sl1d7aqi.fsf@rho.meyering.net","threadId":"11473","inReplyTo":null,"subject":"[PATCH] Don't access line[-1] for a zero-length \"line\" from fgets.","fromName":"Jim Meyering","fromEmail":"jim@meyering.net","sentAt":"2008-01-04T17:37:41Z","receivedAt":"2008-01-04T17:37:41Z","isPatch":true,"sender":{"key":"jim@meyering.net","avatar":"https://avatars.githubusercontent.com/u/710630?v=4"},"body":"A NUL byte at beginning of file, or just after a newline\nwould provoke an invalid buf[-1] access in a few places.\n\n* builtin-grep.c (cmd_grep): Don't access buf[-1].\n* builtin-pack-objects.c (get_object_list): Likewise.\n* builtin-rev-list.c (read_revisions_from_stdin): Likewise.\n* bundle.c (read_bundle_header): Likewise.\n* server-info.c (read_pack_info_file): Likewise.\n* transport.c (insert_packed_refs): Likewise.\n\nSigned-off-by: Jim Meyering <meyering@redhat.com>\n---\n builtin-grep.c         |    2 +-\n builtin-pack-objects.c |    2 +-\n builtin-rev-list.c     |    2 +-\n bundle.c               |    2 +-\n server-info.c          |    2 +-\n transport.c            |    2 +-\n 6 files changed, 6 insertions(+), 6 deletions(-)\n\ndiff --git a/builtin-grep.c b/builtin-grep.c\nindex f1ff8dc..0d6cc73 100644\n--- a/builtin-grep.c\n+++ b/builtin-grep.c\n@@ -644,7 +644,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)\n \t\t\t\tdie(\"'%s': %s\", argv[1], strerror(errno));\n \t\t\twhile (fgets(buf, sizeof(buf), patterns)) {\n \t\t\t\tint len = strlen(buf);\n-\t\t\t\tif (buf[len-1] == '\\n')\n+\t\t\t\tif (len && buf[len-1] == '\\n')\n \t\t\t\t\tbuf[len-1] = 0;\n \t\t\t\t/* ignore empty line like grep does */\n \t\t\t\tif (!buf[0])\ndiff --git a/builtin-pack-objects.c b/builtin-pack-objects.c\nindex e0ce114..a39cb82 100644\n--- a/builtin-pack-objects.c\n+++ b/builtin-pack-objects.c\n@@ -2013,7 +2013,7 @@ static void get_object_list(int ac, const char **av)\n\n \twhile (fgets(line, sizeof(line), stdin) != NULL) {\n \t\tint len = strlen(line);\n-\t\tif (line[len - 1] == '\\n')\n+\t\tif (len && line[len - 1] == '\\n')\n \t\t\tline[--len] = 0;\n \t\tif (!len)\n \t\t\tbreak;\ndiff --git a/builtin-rev-list.c b/builtin-rev-list.c\nindex 1cb5f67..de80158 100644\n--- a/builtin-rev-list.c\n+++ b/builtin-rev-list.c\n@@ -520,7 +520,7 @@ static void read_revisions_from_stdin(struct rev_info *revs)\n\n \twhile (fgets(line, sizeof(line), stdin) != NULL) {\n \t\tint len = strlen(line);\n-\t\tif (line[len - 1] == '\\n')\n+\t\tif (len && line[len - 1] == '\\n')\n \t\t\tline[--len] = 0;\n \t\tif (!len)\n \t\t\tbreak;\ndiff --git a/bundle.c b/bundle.c\nindex 9b9b916..be204d8 100644\n--- a/bundle.c\n+++ b/bundle.c\n@@ -48,7 +48,7 @@ int read_bundle_header(const char *path, struct bundle_header *header)\n \t\t\t: &header->references;\n \t\tchar delim;\n\n-\t\tif (buffer[len - 1] == '\\n')\n+\t\tif (len && buffer[len - 1] == '\\n')\n \t\t\tbuffer[len - 1] = '\\0';\n \t\tif (get_sha1_hex(buffer + offset, sha1)) {\n \t\t\twarning(\"unrecognized header: %s\", buffer);\ndiff --git a/server-info.c b/server-info.c\nindex a051e49..c1c073b 100644\n--- a/server-info.c\n+++ b/server-info.c\n@@ -101,7 +101,7 @@ static int read_pack_info_file(const char *infofile)\n\n \twhile (fgets(line, sizeof(line), fp)) {\n \t\tint len = strlen(line);\n-\t\tif (line[len-1] == '\\n')\n+\t\tif (len && line[len-1] == '\\n')\n \t\t\tline[--len] = 0;\n\n \t\tif (!len)\ndiff --git a/transport.c b/transport.c\nindex 4e151a9..babaa21 100644\n--- a/transport.c\n+++ b/transport.c\n@@ -118,7 +118,7 @@ static void insert_packed_refs(const char *packed_refs, struct ref **list)\n \t\tif (hexval(buffer[0]) > 0xf)\n \t\t\tcontinue;\n \t\tlen = strlen(buffer);\n-\t\tif (buffer[len - 1] == '\\n')\n+\t\tif (len && buffer[len - 1] == '\\n')\n \t\t\tbuffer[--len] = '\\0';\n \t\tif (len < 41)\n \t\t\tcontinue;\n--\n1.5.4.rc2.18.ga0289\n"}]}