mirror of https://github.com/moparisthebest/curl
curl: avoid local drive traversal when saving file (Windows)
curl does not sanitize colons in a remote file name that is used as the local file name. This may lead to a vulnerability on systems where the colon is a special path character. Currently Windows/DOS is the only OS where this vulnerability applies. CVE-2016-0754 Bug: http://curl.haxx.se/docs/adv_20160127B.html
This commit is contained in:
Ray Satiro
Daniel Stenberg
parent
cea1fd7a94
commit
3017d8a8d8
|
|
@ -28,6 +28,7 @@
|
|||
#include "curlx.h"
|
||||
|
||||
#include "tool_cfgable.h"
|
||||
#include "tool_doswin.h"
|
||||
#include "tool_msgs.h"
|
||||
#include "tool_cb_hdr.h"
|
||||
|
||||
|
|
@ -114,18 +115,24 @@ size_t tool_header_cb(void *ptr, size_t size, size_t nmemb, void *userdata)
|
|||
*/
|
||||
len = (ssize_t)cb - (p - str);
|
||||
filename = parse_filename(p, len);
|
||||
if(filename) {
|
||||
outs->filename = filename;
|
||||
outs->alloc_filename = TRUE;
|
||||
outs->is_cd_filename = TRUE;
|
||||
outs->s_isreg = TRUE;
|
||||
outs->fopened = FALSE;
|
||||
outs->stream = NULL;
|
||||
hdrcbdata->honor_cd_filename = FALSE;
|
||||
break;
|
||||
}
|
||||
else
|
||||
if(!filename)
|
||||
return failure;
|
||||
|
||||
#if defined(MSDOS) || defined(WIN32)
|
||||
if(sanitize_file_name(&filename)) {
|
||||
free(filename);
|
||||
return failure;
|
||||
}
|
||||
#endif /* MSDOS || WIN32 */
|
||||
|
||||
outs->filename = filename;
|
||||
outs->alloc_filename = TRUE;
|
||||
outs->is_cd_filename = TRUE;
|
||||
outs->s_isreg = TRUE;
|
||||
outs->fopened = FALSE;
|
||||
outs->stream = NULL;
|
||||
hdrcbdata->honor_cd_filename = FALSE;
|
||||
break;
|
||||
}
|
||||
}
|
||||
|
||||
|
|
@ -181,15 +188,12 @@ static char *parse_filename(const char *ptr, size_t len)
|
|||
}
|
||||
|
||||
/* scan for the end letter and stop there */
|
||||
q = p;
|
||||
while(*q) {
|
||||
if(q[1] && (q[0] == '\\'))
|
||||
q++;
|
||||
else if(q[0] == stop)
|
||||
for(q = p; *q; ++q) {
|
||||
if(*q == stop) {
|
||||
*q = '\0';
|
||||
break;
|
||||
q++;
|
||||
}
|
||||
}
|
||||
*q = '\0';
|
||||
|
||||
/* make sure the file name doesn't end in \r or \n */
|
||||
q = strchr(p, '\r');
|
||||
|
|
|
|||
|
|
@ -85,42 +85,106 @@ __pragma(warning(pop))
|
|||
# include <fcntl.h> /* _use_lfn(f) prototype */
|
||||
#endif
|
||||
|
||||
static const char *msdosify (const char *file_name);
|
||||
static char *rename_if_dos_device_name (char *file_name);
|
||||
static char *msdosify(const char *file_name);
|
||||
static char *rename_if_dos_device_name(const char *file_name);
|
||||
|
||||
|
||||
/*
|
||||
* sanitize_dos_name: returns a newly allocated string holding a
|
||||
* valid file name which will be a transformation of given argument
|
||||
* in case this wasn't already a valid file name.
|
||||
*
|
||||
* This function takes ownership of given argument, free'ing it before
|
||||
* returning. Caller is responsible of free'ing returned string. Upon
|
||||
* out of memory condition function returns NULL.
|
||||
*/
|
||||
|
||||
char *sanitize_dos_name(char *file_name)
|
||||
Sanitize *file_name.
|
||||
Success: (CURLE_OK) *file_name points to a sanitized version of the original.
|
||||
This function takes ownership of the original *file_name and frees it.
|
||||
Failure: (!= CURLE_OK) *file_name is unchanged.
|
||||
*/
|
||||
CURLcode sanitize_file_name(char **file_name)
|
||||
{
|
||||
char new_name[PATH_MAX];
|
||||
size_t len;
|
||||
char *p, *sanitized;
|
||||
|
||||
if(!file_name)
|
||||
return NULL;
|
||||
/* Calculate the maximum length of a filename.
|
||||
FILENAME_MAX is often the same as PATH_MAX, in other words it does not
|
||||
discount the path information. PATH_MAX size is calculated based on:
|
||||
<drive-letter><colon><path-sep><max-filename-len><NULL> */
|
||||
const size_t max_filename_len = PATH_MAX - 3 - 1;
|
||||
|
||||
if(strlen(file_name) >= PATH_MAX)
|
||||
file_name[PATH_MAX-1] = '\0'; /* truncate it */
|
||||
if(!file_name || !*file_name)
|
||||
return CURLE_BAD_FUNCTION_ARGUMENT;
|
||||
|
||||
strcpy(new_name, msdosify(file_name));
|
||||
len = strlen(*file_name);
|
||||
|
||||
Curl_safefree(file_name);
|
||||
if(len >= max_filename_len)
|
||||
len = max_filename_len - 1;
|
||||
|
||||
return strdup(rename_if_dos_device_name(new_name));
|
||||
sanitized = malloc(len + 1);
|
||||
|
||||
if(!sanitized)
|
||||
return CURLE_OUT_OF_MEMORY;
|
||||
|
||||
strncpy(sanitized, *file_name, len);
|
||||
sanitized[len] = '\0';
|
||||
|
||||
for(p = sanitized; *p; ++p ) {
|
||||
const char *banned;
|
||||
if(1 <= *p && *p <= 31) {
|
||||
*p = '_';
|
||||
continue;
|
||||
}
|
||||
for(banned = "|<>/\\\":?*"; *banned; ++banned) {
|
||||
if(*p == *banned) {
|
||||
*p = '_';
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#ifdef MSDOS
|
||||
/* msdosify checks for more banned characters for MSDOS, however it allows
|
||||
for some path information to pass through. since we are sanitizing only a
|
||||
filename and cannot allow a path it's important this call be done in
|
||||
addition to and not instead of the banned character check above. */
|
||||
p = msdosify(sanitized);
|
||||
if(!p) {
|
||||
free(sanitized);
|
||||
return CURLE_BAD_FUNCTION_ARGUMENT;
|
||||
}
|
||||
sanitized = p;
|
||||
len = strlen(sanitized);
|
||||
#endif
|
||||
|
||||
p = rename_if_dos_device_name(sanitized);
|
||||
if(!p) {
|
||||
free(sanitized);
|
||||
return CURLE_BAD_FUNCTION_ARGUMENT;
|
||||
}
|
||||
sanitized = p;
|
||||
len = strlen(sanitized);
|
||||
|
||||
/* dos_device_name rename will rename a device name, possibly changing the
|
||||
length. If the length is too long now we can't truncate it because we
|
||||
could end up with a device name. In practice this shouldn't be a problem
|
||||
because device names are short, but you never know. */
|
||||
if(len >= max_filename_len) {
|
||||
free(sanitized);
|
||||
return CURLE_BAD_FUNCTION_ARGUMENT;
|
||||
}
|
||||
|
||||
*file_name = sanitized;
|
||||
return CURLE_OK;
|
||||
}
|
||||
|
||||
/* The following functions are taken with modification from the DJGPP
|
||||
* port of tar 1.12. They use algorithms originally from DJTAR. */
|
||||
/* The functions msdosify, rename_if_dos_device_name and __crt0_glob_function
|
||||
* were taken with modification from the DJGPP port of tar 1.12. They use
|
||||
* algorithms originally from DJTAR.
|
||||
*/
|
||||
|
||||
static const char *msdosify (const char *file_name)
|
||||
/*
|
||||
Extra sanitization MSDOS for file_name.
|
||||
Returns a copy of file_name that is sanitized by MSDOS standards.
|
||||
Warning: path information may pass through. For sanitizing a filename use
|
||||
sanitize_file_name which calls this function after sanitizing path info.
|
||||
*/
|
||||
static char *msdosify(const char *file_name)
|
||||
{
|
||||
static char dos_name[PATH_MAX];
|
||||
char dos_name[PATH_MAX];
|
||||
static const char illegal_chars_dos[] = ".+, ;=[]" /* illegal in DOS */
|
||||
"|<>\\\":?*"; /* illegal in DOS & W95 */
|
||||
static const char *illegal_chars_w95 = &illegal_chars_dos[8];
|
||||
|
|
@ -201,15 +265,20 @@ static const char *msdosify (const char *file_name)
|
|||
}
|
||||
|
||||
*d = '\0';
|
||||
return dos_name;
|
||||
return strdup(dos_name);
|
||||
}
|
||||
|
||||
static char *rename_if_dos_device_name (char *file_name)
|
||||
/*
|
||||
Rename file_name if it's a representation of a device name.
|
||||
Returns a copy of file_name, and the copy will have contents different from the
|
||||
original if a device name was found.
|
||||
*/
|
||||
static char *rename_if_dos_device_name(const char *file_name)
|
||||
{
|
||||
/* We could have a file whose name is a device on MS-DOS. Trying to
|
||||
* retrieve such a file would fail at best and wedge us at worst. We need
|
||||
* to rename such files. */
|
||||
char *base;
|
||||
char *p, *base;
|
||||
struct_stat st_buf;
|
||||
char fname[PATH_MAX];
|
||||
|
||||
|
|
@ -219,7 +288,7 @@ static char *rename_if_dos_device_name (char *file_name)
|
|||
if(((stat(base, &st_buf)) == 0) && (S_ISCHR(st_buf.st_mode))) {
|
||||
size_t blen = strlen(base);
|
||||
|
||||
if(strlen(fname) >= PATH_MAX-1) {
|
||||
if(strlen(fname) == PATH_MAX-1) {
|
||||
/* Make room for the '_' */
|
||||
blen--;
|
||||
base[blen] = '\0';
|
||||
|
|
@ -227,9 +296,54 @@ static char *rename_if_dos_device_name (char *file_name)
|
|||
/* Prepend a '_'. */
|
||||
memmove(base + 1, base, blen + 1);
|
||||
base[0] = '_';
|
||||
strcpy(file_name, fname);
|
||||
}
|
||||
return file_name;
|
||||
|
||||
/* The above stat check does not identify devices for me in Windows 7. For
|
||||
example a stat on COM1 returns a regular file S_IFREG. According to MSDN
|
||||
stat doc that is the correct behavior, so I assume the above code is
|
||||
legacy, maybe MSDOS or DJGPP specific? */
|
||||
|
||||
/* Rename devices.
|
||||
Examples: CON => _CON, CON.EXT => CON_EXT, CON:ADS => CON_ADS */
|
||||
for(p = fname; p; p = (p == fname && fname != base ? base : NULL)) {
|
||||
size_t p_len;
|
||||
int x = (curl_strnequal(p, "CON", 3) ||
|
||||
curl_strnequal(p, "PRN", 3) ||
|
||||
curl_strnequal(p, "AUX", 3) ||
|
||||
curl_strnequal(p, "NUL", 3)) ? 3 :
|
||||
(curl_strnequal(p, "CLOCK$", 6)) ? 6 :
|
||||
(curl_strnequal(p, "COM", 3) || curl_strnequal(p, "LPT", 3)) ?
|
||||
(('1' <= p[3] && p[3] <= '9') ? 4 : 3) : 0;
|
||||
|
||||
if(!x)
|
||||
continue;
|
||||
|
||||
/* the devices may be accessible with an extension or ADS, for
|
||||
example CON.AIR and CON:AIR both access console */
|
||||
if(p[x] == '.' || p[x] == ':') {
|
||||
p[x] = '_';
|
||||
continue;
|
||||
}
|
||||
else if(p[x]) /* no match */
|
||||
continue;
|
||||
|
||||
p_len = strlen(p);
|
||||
|
||||
if(strlen(fname) == PATH_MAX-1) {
|
||||
/* Make room for the '_' */
|
||||
p_len--;
|
||||
p[p_len] = '\0';
|
||||
}
|
||||
/* Prepend a '_'. */
|
||||
memmove(p + 1, p, p_len + 1);
|
||||
p[0] = '_';
|
||||
|
||||
/* if fname was just modified then the basename pointer must be updated */
|
||||
if(p == fname)
|
||||
base = basename(fname);
|
||||
}
|
||||
|
||||
return strdup(fname);
|
||||
}
|
||||
|
||||
#if defined(MSDOS) && (defined(__DJGPP__) || defined(__GO32__))
|
||||
|
|
|
|||
|
|
@ -25,7 +25,7 @@
|
|||
|
||||
#if defined(MSDOS) || defined(WIN32)
|
||||
|
||||
char *sanitize_dos_name(char *file_name);
|
||||
CURLcode sanitize_file_name(char **filename);
|
||||
|
||||
#if defined(MSDOS) && (defined(__DJGPP__) || defined(__GO32__))
|
||||
|
||||
|
|
|
|||
|
|
@ -543,26 +543,37 @@ static CURLcode operate_do(struct GlobalConfig *global,
|
|||
result = get_url_file_name(&outfile, this_url);
|
||||
if(result)
|
||||
goto show_error;
|
||||
|
||||
#if defined(MSDOS) || defined(WIN32)
|
||||
result = sanitize_file_name(&outfile);
|
||||
if(result) {
|
||||
Curl_safefree(outfile);
|
||||
goto show_error;
|
||||
}
|
||||
#endif /* MSDOS || WIN32 */
|
||||
|
||||
if(!*outfile && !config->content_disposition) {
|
||||
helpf(global->errors, "Remote file name has no length!\n");
|
||||
result = CURLE_WRITE_ERROR;
|
||||
goto quit_urls;
|
||||
}
|
||||
#if defined(MSDOS) || defined(WIN32)
|
||||
/* For DOS and WIN32, we do some major replacing of
|
||||
bad characters in the file name before using it */
|
||||
outfile = sanitize_dos_name(outfile);
|
||||
if(!outfile) {
|
||||
result = CURLE_OUT_OF_MEMORY;
|
||||
goto show_error;
|
||||
}
|
||||
#endif /* MSDOS || WIN32 */
|
||||
}
|
||||
else if(urls) {
|
||||
/* fill '#1' ... '#9' terms from URL pattern */
|
||||
char *storefile = outfile;
|
||||
result = glob_match_url(&outfile, storefile, urls);
|
||||
Curl_safefree(storefile);
|
||||
|
||||
#if defined(MSDOS) || defined(WIN32)
|
||||
if(!result) {
|
||||
result = sanitize_file_name(&outfile);
|
||||
if(result) {
|
||||
Curl_safefree(outfile);
|
||||
goto show_error;
|
||||
}
|
||||
}
|
||||
#endif /* MSDOS || WIN32 */
|
||||
|
||||
if(result) {
|
||||
/* bad globbing */
|
||||
warnf(config->global, "bad output glob!\n");
|
||||
|
|
|
|||
Loading…
Reference in New Issue