diff options
Diffstat (limited to 'applets/applets.c')
| -rw-r--r-- | applets/applets.c | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/applets/applets.c b/applets/applets.c index 66bcc42de..32c63d1e0 100644 --- a/applets/applets.c +++ b/applets/applets.c @@ -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) { |