From: Masahiro Yamada masahiroy@kernel.org
mainline inclusion from mainline-5.8 commit ac5100f54329676469688d1b5415cd8d6428c909 category: bugfix bugzilla: 46847 CVE: NA
-----------------------------------------------
modpost uses grab_file() to open a file, but it is not suitable for a text file because the mmap'ed file is not terminated by null byte. Actually, I see some issues for the use of grab_file().
The new helper, read_text_file() loads the whole file content into a malloc'ed buffer, and appends a null byte. Then, get_line() reads each line.
To handle text files, I intend to replace as follows:
grab_file() -> read_text_file() get_new_line() -> get_line()
Signed-off-by: Masahiro Yamada masahiroy@kernel.org Signed-off-by: Wang Wensheng wangwensheng4@huawei.com Reviewed-by: Jian Cheng cj.chengjian@huawei.com Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- scripts/mod/modpost.c | 49 +++++++++++++++++++++++++++++++++++++++++++ scripts/mod/modpost.h | 2 ++ 2 files changed, 51 insertions(+)
diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c index 91a80036c05d5..99334521909be 100644 --- a/scripts/mod/modpost.c +++ b/scripts/mod/modpost.c @@ -118,6 +118,55 @@ void *do_nofail(void *ptr, const char *expr) return ptr; }
+char *read_text_file(const char *filename) +{ + struct stat st; + size_t nbytes; + int fd; + char *buf; + + fd = open(filename, O_RDONLY); + if (fd < 0) { + perror(filename); + exit(1); + } + + if (fstat(fd, &st) < 0) { + perror(filename); + exit(1); + } + + buf = NOFAIL(malloc(st.st_size + 1)); + + nbytes = st.st_size; + + while (nbytes) { + ssize_t bytes_read; + + bytes_read = read(fd, buf, nbytes); + if (bytes_read < 0) { + perror(filename); + exit(1); + } + + nbytes -= bytes_read; + } + buf[st.st_size] = '\0'; + + close(fd); + + return buf; +} + +char *get_line(char **stringp) +{ + /* do not return the unwanted extra line at EOF */ + if (*stringp && **stringp == '\0') + return NULL; + + return strsep(stringp, "\n"); +} + /* A list of all modules we processed */ static struct module *modules;
diff --git a/scripts/mod/modpost.h b/scripts/mod/modpost.h index 8453d6ac2f77e..ff809119f82bb 100644 --- a/scripts/mod/modpost.h +++ b/scripts/mod/modpost.h @@ -185,6 +185,8 @@ void maybe_frob_rcs_version(const char *modfilename, void get_src_version(const char *modname, char sum[], unsigned sumlen);
/* from modpost.c */ +char *read_text_file(const char *filename); +char *get_line(char **stringp); void *grab_file(const char *filename, unsigned long *size); char* get_next_line(unsigned long *pos, void *file, unsigned long size); void release_file(void *file, unsigned long size);