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hopefully bulletproof is_subpath

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This was SVN commit r497.
This commit is contained in:
janwas 2004-06-13 19:13:32 +00:00
parent da1e6df5f0
commit ed23cb7cc1
1 changed files with 31 additions and 18 deletions
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49
source/lib/res/vfs.cpp
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@ -723,6 +723,34 @@ static void vfs_shutdown(void)
}
static bool is_subpath(const char* s1, const char* s2)
{
// make sure s1 is the shorter string
if(strlen(s1) > strlen(s2))
std::swap(s1, s2);
int c1 = 0, last_c1, c2;
for(;;)
{
last_c1 = c1;
c1 = *s1++, c2 = *s2++;
// end of s1 reached
if(c1 == '\0')
{
// s1 matched s2 up until:
if(c2 == '\0' || // its end (i.e. they're equal length)
c2 == '/' || // start of next component
last_c1 == '/') // ", but both have a trailing slash
return true;
}
if(c1 != c2)
return false;
}
}
// mount either a single archive or a directory into the VFS at
// <vfs_mount_point>, which is created if it does not yet exist.
// new files override the previous VFS contents if pri(ority) is higher.
@ -733,36 +761,21 @@ int vfs_mount(const char* const vfs_mount_point, const char* const name, const u
{
ONCE(atexit2(vfs_shutdown));
const size_t name_len = strlen(name);
// PROBLEM! rejects valid (but stupid) paths
// aa/bbb/cccc
// aa/bbb/cccc/ NO
// aa/bbb/cccc/d NO
// aa/bbb/c YES
// aa/bbb/d YES
// aa/bbb
// mods/offical
// mods/of
CHECK_PATH(name);
// make sure it's not already mounted, i.e. in mounts.
// also prevents mounting a parent directory of a previously mounted
// directory, or vice versa. example: mount $install/data and then
// $install/data/mods/official - mods/official would also be accessible
// from the first mount point - bad.
// no matter if it's an archive - still shouldn't be a "subpath".
for(MountIt it = mounts.begin(); it != mounts.end(); ++it)
/// {
const size_t cmp_len = MIN(it->f_name.length(), name_len);
if(strncmp(name, it->f_name.c_str(), cmp_len) == 0)
if(is_subpath(name, it->f_name.c_str()))
{
debug_warn("vfs_mount: already mounted");
return -1;
}
CHECK_PATH(name);
// disallow "." because "./" isn't supported on Windows.
// it would also create a loophole for the parent dir check above.
// "./" and "/." are caught by CHECK_PATH.