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authorPeter Seebach <seebs@eee12.(none)>2010-03-24 19:31:58 -0500
committerPeter Seebach <seebs@eee12.(none)>2010-03-25 16:43:13 -0500
commit2c389272304f2710b317f185c6fb057458bc9027 (patch)
treeee35ad5102fc6a17f284c693c19a3a028a3114ea /pseudo_util.c
parent4b555b46b36ccd50a1130238e02a2e2d41b50366 (diff)
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initial chroot() support
Add chroot() and a large number of things needed to make it work. The list of intercepted calls is large but not exhaustive.
Diffstat (limited to 'pseudo_util.c')
-rw-r--r--pseudo_util.c76
1 files changed, 45 insertions, 31 deletions
diff --git a/pseudo_util.c b/pseudo_util.c
index 4bc2d5a..dcd571f 100644
--- a/pseudo_util.c
+++ b/pseudo_util.c
@@ -42,8 +42,8 @@ int pseudo_util_debug_fd = 2;
static int debugged_newline = 1;
static char pid_text[32];
static size_t pid_len;
-static int pseudo_append_element(char **newpath, size_t *allocated, char **current, const char *element, size_t elen, int leave_last);
-static int pseudo_append_elements(char **newpath, size_t *allocated, char **current, const char *elements, size_t elen, int leave_last);
+static int pseudo_append_element(char **pnewpath, char **proot, size_t *pallocated, char **pcurrent, const char *element, size_t elen, int leave_this);
+static int pseudo_append_elements(char **newpath, char **root, size_t *allocated, char **current, const char *elements, size_t elen, int leave_last);
extern char **environ;
static ssize_t pseudo_max_pathlen = -1;
static ssize_t pseudo_sys_max_pathlen = -1;
@@ -136,18 +136,22 @@ pseudo_new_pid() {
* the symlink, appending each element in turn the same way.
*/
static int
-pseudo_append_element(char **pnewpath, size_t *pallocated, char **pcurrent, const char *element, size_t elen, int leave_this) {
+pseudo_append_element(char **pnewpath, char **proot, size_t *pallocated, char **pcurrent, const char *element, size_t elen, int leave_this) {
static int link_recursion = 0;
size_t curlen, allocated;
- char *newpath, *current;
+ char *newpath, *current, *root;
struct stat64 buf;
- if (!pnewpath || !*pnewpath || !pallocated || !pcurrent || !*pcurrent || !element) {
+ if (!pnewpath || !*pnewpath ||
+ !pcurrent || !*pcurrent ||
+ !proot || !*proot ||
+ !pallocated || !element) {
pseudo_diag("pseudo_append_element: invalid args.\n");
return -1;
}
newpath = *pnewpath;
allocated = *pallocated;
current = *pcurrent;
+ root = *proot;
/* sanity-check: ignore // or /./ */
if (elen == 0 || (elen == 1 && *element == '.')) {
return 1;
@@ -155,12 +159,12 @@ pseudo_append_element(char **pnewpath, size_t *pallocated, char **pcurrent, cons
/* backtrack for .. */
if (elen == 2 && element[0] == '.' && element[1] == '.') {
/* if newpath's whole contents are '/', do nothing */
- if (current <= newpath + 1)
+ if (current <= root + 1)
return 1;
/* backtrack to the character before the / */
current -= 2;
/* now find the previous slash */
- while (current > newpath && *current != '/') {
+ while (current > root && *current != '/') {
--current;
}
/* and point to the nul just past it */
@@ -181,11 +185,13 @@ pseudo_append_element(char **pnewpath, size_t *pallocated, char **pcurrent, cons
}
memcpy(bigger, newpath, curlen);
current = bigger + curlen;
+ root = bigger + (root - newpath);
free(newpath);
newpath = bigger;
allocated = big;
*pnewpath = newpath;
*pcurrent = current;
+ *proot = root;
*pallocated = allocated;
}
memcpy(current, element, elen);
@@ -225,7 +231,7 @@ pseudo_append_element(char **pnewpath, size_t *pallocated, char **pcurrent, cons
/* append all the elements in series */
*pcurrent = current;
++link_recursion;
- retval = pseudo_append_elements(pnewpath, pallocated, pcurrent, linkbuf, linklen, 0);
+ retval = pseudo_append_elements(pnewpath, proot, pallocated, pcurrent, linkbuf, linklen, 0);
--link_recursion;
return retval;
}
@@ -238,10 +244,13 @@ pseudo_append_element(char **pnewpath, size_t *pallocated, char **pcurrent, cons
}
static int
-pseudo_append_elements(char **newpath, size_t *allocated, char **current, const char *element, size_t elen, int leave_last) {
+pseudo_append_elements(char **newpath, char **root, size_t *allocated, char **current, const char *element, size_t elen, int leave_last) {
int retval = 1;
const char * start = element;
- if (!newpath || !current || !element || !*newpath || !*current) {
+ if (!newpath || !*newpath ||
+ !root || !*root ||
+ !current || !*current ||
+ !element) {
pseudo_diag("pseudo_append_elements: invalid arguments.");
return -1;
}
@@ -259,13 +268,13 @@ pseudo_append_elements(char **newpath, size_t *allocated, char **current, const
break;
case 1: /* path => '?/' */
if (*element != '.') {
- if (pseudo_append_element(newpath, allocated, current, element, this_elen, leave_this) == -1) {
+ if (pseudo_append_element(newpath, root, allocated, current, element, this_elen, leave_this) == -1) {
retval = -1;
}
}
break;
default:
- if (pseudo_append_element(newpath, allocated, current, element, this_elen, leave_this) == -1) {
+ if (pseudo_append_element(newpath, root, allocated, current, element, this_elen, leave_this) == -1) {
retval = -1;
}
break;
@@ -284,35 +293,40 @@ pseudo_append_elements(char **newpath, size_t *allocated, char **current, const
* we ignore base.
*/
char *
-pseudo_fix_path(char *base, const char *path, size_t baselen, size_t *lenp, int leave_last) {
+pseudo_fix_path(const char *base, const char *path, size_t rootlen, size_t baselen, size_t *lenp, int leave_last) {
size_t newpathlen, pathlen;
char *newpath;
char *current;
+ char *effective_root;
if (!path) {
pseudo_diag("can't fix empty path.\n");
return 0;
}
pathlen = strlen(path);
+ newpathlen = pathlen;
+ if (baselen && path[0] != '/') {
+ newpathlen += baselen + 2;
+ }
/* allow a bit of slush. overallocating a bit won't
* hurt. rounding to 256's in the hopes that it makes life
* easier for the library.
*/
- if (path[0] == '/') {
- newpathlen = round_up(pathlen + 1, 256);
- newpath = malloc(newpathlen);
- if (!newpath) {
- pseudo_diag("allocation failed seeking memory for path (%s).\n", path);
- return 0;
- }
- current = newpath;
- ++path;
- } else {
- newpathlen = round_up(baselen + pathlen + 2, 256);
- newpath = malloc(newpathlen);
- memcpy(newpath, base, baselen);
- current = newpath + baselen;
+ newpathlen = round_up(newpathlen, 256);
+ newpath = malloc(newpathlen);
+ if (!newpath) {
+ pseudo_diag("allocation failed seeking memory for path (%s).\n", path);
+ return 0;
+ }
+ current = newpath;
+ if (baselen) {
+ memcpy(current, base, baselen);
+ current += baselen;
}
+ /* "root" is a pointer to the beginning of the *modifiable*
+ * part of the string; you can't back up over it.
+ */
+ effective_root = newpath + rootlen;
*current++ = '/';
*current = '\0';
/* at any given point:
@@ -323,12 +337,12 @@ pseudo_fix_path(char *base, const char *path, size_t baselen, size_t *lenp, int
* oldpath is the starting point of path
* (path - oldpath) is how far into path we are
*/
- if (pseudo_append_elements(&newpath, &newpathlen, &current, path, pathlen, leave_last) != -1) {
+ if (pseudo_append_elements(&newpath, &effective_root, &newpathlen, &current, path, pathlen, leave_last) != -1) {
--current;
- if (*current == '/') {
+ if (*current == '/' && current > effective_root) {
*current = '\0';
}
- pseudo_debug(3, "%s + %s => <%s>\n",
+ pseudo_debug(5, "%s + %s => <%s>\n",
base ? base : "<nil>",
path ? path : "<nil>",
newpath ? newpath : "<nil>");
@@ -478,7 +492,7 @@ pseudo_get_prefix(char *pathname) {
s += snprintf(s, pseudo_path_max() - (s - mypath), "/%s",
pathname);
}
- tmp_path = pseudo_fix_path(NULL, mypath, 0, 0, AT_SYMLINK_NOFOLLOW);
+ tmp_path = pseudo_fix_path(NULL, mypath, 0, 0, 0, AT_SYMLINK_NOFOLLOW);
/* point s to the end of the fixed path */
if (strlen(tmp_path) >= pseudo_path_max()) {
pseudo_diag("Can't expand path '%s' -- expansion exceeds %d.\n",