1
0
mirror of https://github.com/gryf/wmaker.git synced 2025-12-19 12:28:22 +01:00

WUtil: rewrote wcopy_file for better error handling and to fix Coverity #50234

The original code used the libc "fopen" kind of operation, which are handy
when manipulating text files, but:
 - bring an overhead for binary files that we don't need here;
 - does not provide the mechanisms for safe error handling and special cases

As Coverity reported a Time-of-Check/Time-of-Use type of security issue,
took the opportunity to fix it and increased the size of the buffer used
for data to allow better use of modern disk performances.

Signed-off-by: Christophe CURIS <christophe.curis@free.fr>
Signed-off-by: Carlos R. Mafra <crmafra@gmail.com>
This commit is contained in:
Christophe CURIS
2014-11-15 19:40:30 +01:00
committed by Carlos R. Mafra
parent 662b83769a
commit 155e1f1fe1

View File

@@ -23,7 +23,9 @@
#include "WUtil.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
@@ -422,60 +424,104 @@ char *wfindfileinarray(WMPropList *array, const char *file)
return NULL;
}
int wcopy_file(const char *dir, const char *src_file, const char *dest_file)
int wcopy_file(const char *dest_dir, const char *src_file, const char *dest_file)
{
FILE *src, *dst;
size_t nread, nwritten;
char *dstpath;
struct stat st;
char buf[4096];
char *path_dst;
int fd_src, fd_dst;
struct stat stat_src;
mode_t permission_dst;
const size_t buffer_size = 2 * 1024 * 1024; /* 4MB is a decent start choice to allow the OS to take advantage of modern disk's performance */
char *buffer; /* The buffer is not created on the stack to avoid possible stack overflow as our buffer is big */
/* only to a directory */
if (stat(dir, &st) != 0 || !S_ISDIR(st.st_mode))
return -1;
/* only copy files */
if (stat(src_file, &st) != 0 || !S_ISREG(st.st_mode))
return -1;
do {
src = fopen(src_file, "rb");
} while ((src == NULL) && (errno == EINTR));
if (src == NULL) {
werror(_("Could not open input file \"%s\""), src_file);
try_again_src:
fd_src = open(src_file, O_RDONLY | O_NOFOLLOW);
if (fd_src == -1) {
if (errno == EINTR)
goto try_again_src;
werror(_("Could not open input file \"%s\": %s"), src_file, strerror(errno));
return -1;
}
dstpath = wstrconcat(dir, dest_file);
do {
dst = fopen(dstpath, "wb");
} while ((dst == NULL) && (errno == EINTR));
if (dst == NULL) {
werror(_("Could not create target file \"%s\""), dstpath);
wfree(dstpath);
fclose(src);
/* Only accept to copy regular files */
if (fstat(fd_src, &stat_src) != 0 || !S_ISREG(stat_src.st_mode)) {
close(fd_src);
return -1;
}
do {
nread = fread(buf, 1, sizeof(buf), src);
if (ferror(src))
break;
path_dst = wstrconcat(dest_dir, dest_file);
try_again_dst:
fd_dst = open(path_dst, O_WRONLY | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
if (fd_dst == -1) {
if (errno == EINTR)
goto try_again_dst;
werror(_("Could not create target file \"%s\": %s"), path_dst, strerror(errno));
wfree(path_dst);
close(fd_src);
return -1;
}
nwritten = fwrite(buf, 1, nread, dst);
if (ferror(dst) || feof(src) || nread != nwritten)
break;
buffer = malloc(buffer_size); /* Don't use wmalloc to avoid the memset(0) we don't need */
if (buffer == NULL) {
werror(_("could not allocate memory for the copy buffer"));
close(fd_dst);
goto cleanup_and_return_failure;
}
} while (1);
for (;;) {
ssize_t size_data;
const char *write_ptr;
size_t write_remain;
if (ferror(src) || ferror(dst))
unlink(dstpath);
try_again_read:
size_data = read(fd_src, buffer, buffer_size);
if (size_data == 0)
break; /* End of File have been reached */
if (size_data < 0) {
if (errno == EINTR)
goto try_again_read;
werror(_("could not read from file \"%s\": %s"), src_file, strerror(errno));
close(fd_dst);
goto cleanup_and_return_failure;
}
fclose(src);
fchmod(fileno(dst), st.st_mode);
fsync(fileno(dst));
if (fclose(dst))
wwarning("error occured during fclose(\"%s\")", dstpath);
wfree(dstpath);
write_ptr = buffer;
write_remain = size_data;
while (write_remain > 0) {
ssize_t write_done;
try_again_write:
write_done = write(fd_dst, write_ptr, write_remain);
if (write_done < 0) {
if (errno == EINTR)
goto try_again_write;
werror(_("could not write data to file \"%s\": %s"), path_dst, strerror(errno));
close(fd_dst);
goto cleanup_and_return_failure;
}
write_ptr += write_done;
write_remain -= write_done;
}
}
/* Keep only the permission-related part of the field: */
permission_dst = stat_src.st_mode & (S_IRWXU | S_IRWXG | S_IRWXO | S_ISUID | S_ISGID | S_ISVTX);
if (fchmod(fd_dst, permission_dst) != 0)
wwarning(_("could not set permission 0%03o on file \"%s\": %s"),
permission_dst, path_dst, strerror(errno));
if (close(fd_dst) != 0) {
werror(_("could not close the file \"%s\": %s"), path_dst, strerror(errno));
cleanup_and_return_failure:
free(buffer);
wfree(path_dst);
close(fd_src);
unlink(path_dst);
return -1;
}
free(buffer);
wfree(path_dst);
close(fd_src);
return 0;
}