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fix suid config handling

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This commit is contained in:
Denis Vlasenko 2007-05-02 23:01:32 +00:00
parent f92df58d3d
commit 3bc18253b0
2 changed files with 27 additions and 16 deletions
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39
applets/applets.c
View File

@ -110,9 +110,6 @@ static char *get_trimmed_slice(char *s, char *e)
/* Don't depend on the tools to combine strings. */
static const char config_file[] = "/etc/busybox.conf";
/* There are 4 chars + 1 nul for each of user/group/other. */
static const char mode_chars[] = "Ssx-\0Ssx-\0Ttx-";
/* We don't supply a value for the nul, so an index adjustment is
* necessary below. Also, we use unsigned short here to save some
* space even though these are really mode_t values. */
@ -257,6 +254,9 @@ static void parse_config_file(void)
e = skip_whitespace(e+1);
for (i = 0; i < 3; i++) {
/* There are 4 chars + 1 nul for each of user/group/other. */
static const char mode_chars[] = "Ssx-\0" "Ssx-\0" "Ttx-";
const char *q;
q = strchrnul(mode_chars + 5*i, *e++);
if (!*q) {
@ -337,7 +337,8 @@ static inline void parse_config_file(void)
#if ENABLE_FEATURE_SUID
static void check_suid(const struct bb_applet *applet)
{
uid_t rgid; /* real gid */
uid_t uid;
gid_t rgid; /* real gid */
if (ruid == 0) /* set by parse_config_file() */
return; /* run by root - no need to check more */
@ -368,16 +369,24 @@ static void check_suid(const struct bb_applet *applet)
if (!(m & S_IXOTH)) /* is x bit not set ? */
bb_error_msg_and_die("you have no permission to run this applet!");
if (sct->m_gid != 0) {
/* _both_ have to be set for sgid */
if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
xsetgid(sct->m_gid);
} else xsetgid(rgid); /* no sgid -> drop */
}
if (sct->m_uid != 0) {
if (sct->m_mode & S_ISUID) xsetuid(sct->m_uid);
else xsetuid(ruid); /* no suid -> drop */
}
/* _both_ sgid and group_exec have to be set for setegid */
if ((sct->m_mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP))
rgid = sct->m_gid;
/* else (no setegid) we will set egid = rgid */
/* We set effective AND saved ids. If saved-id is not set
* like we do below, seteiud(0) can still later succeed! */
if (setresgid(-1, rgid, rgid))
bb_perror_msg_and_die("setresgid");
/* do we have to set effective uid? */
uid = ruid;
if (sct->m_mode & S_ISUID)
uid = sct->m_uid;
/* else (no seteuid) we will set euid = ruid */
if (setresuid(-1, uid, uid))
bb_perror_msg_and_die("setresuid");
return;
}
#if !ENABLE_FEATURE_SUID_CONFIG_QUIET
@ -393,6 +402,8 @@ static void check_suid(const struct bb_applet *applet)
#endif
if (applet->need_suid == _BB_SUID_ALWAYS) {
/* Real uid is not 0. If euid isn't 0 too, suid bit
* is most probably not set on our executable */
if (geteuid())
bb_error_msg_and_die("applet requires root privileges!");
} else if (applet->need_suid == _BB_SUID_NEVER) {

4
libbb/xfuncs.c
View File

@ -386,13 +386,13 @@ char *bin2hex(char *p, const char *cp, int count)
// setgid() will fail and we'll _still_be_root_, which is bad.)
void xsetgid(gid_t gid)
{
if (setgid(gid)) bb_error_msg_and_die("setgid");
if (setgid(gid)) bb_perror_msg_and_die("setgid");
}
// Die with an error message if we can't set uid. (See xsetgid() for why.)
void xsetuid(uid_t uid)
{
if (setuid(uid)) bb_error_msg_and_die("setuid");
if (setuid(uid)) bb_perror_msg_and_die("setuid");
}
// Return how long the file at fd is, if there's any way to determine it.