diff options
| -rw-r--r-- | Config.in | 10 | ||||
| -rw-r--r-- | libbb/appletlib.c | 67 |
2 files changed, 43 insertions, 34 deletions
@@ -350,7 +350,15 @@ config FEATURE_SUID_CONFIG by checking /etc/busybox.conf. (This is sort of a poor man's sudo.) The format of this file is as follows: - <applet> = [Ssx-][Ssx-][x-] (<username>|<uid>).(<groupname>|<gid>) + APPLET = [Ssx-][Ssx-][x-] USER.GROUP + + s: This user/group are allowed to execute APPLET. + APPLET will run under USER or GROUP. + x: User/group/others are allowed to execute APPLET. + No UID/GID change will be done when it is run. + S: This user/group are NOT allowed to execute APPLET. + APPLET will run under USER or GROUP. + -: User/group/others are not allowed to execute APPLET. An example might help: diff --git a/libbb/appletlib.c b/libbb/appletlib.c index 269cc5bbf..ed60a1a0a 100644 --- a/libbb/appletlib.c +++ b/libbb/appletlib.c @@ -281,21 +281,11 @@ static char *get_trimmed_slice(char *s, char *e) return skip_whitespace(s); } -/* Don't depend on the tools to combine strings. */ -static const char config_file[] ALIGN1 = "/etc/busybox.conf"; - -/* 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. */ -static const unsigned short mode_mask[] ALIGN2 = { - /* SST sst xxx --- */ - S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* user */ - S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* group */ - 0, S_IXOTH, S_IXOTH, 0 /* other */ -}; - static void parse_config_file(void) { + /* Don't depend on the tools to combine strings. */ + static const char config_file[] ALIGN1 = "/etc/busybox.conf"; + struct suid_config_t *sct_head; int applet_no; FILE *f; @@ -411,7 +401,7 @@ static void parse_config_file(void) * up when the busybox configuration is changed. */ applet_no = find_applet_by_name(s); if (applet_no >= 0) { - int i; + unsigned i; struct suid_config_t *sct; /* Note: We currently don't check for duplicates! @@ -429,17 +419,24 @@ 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[] ALIGN1 = "Ssx-\0" "Ssx-\0" "Ttx-"; - - const char *q; - q = strchrnul(mode_chars + 5*i, *e++); - if (!*q) { + /* There are 4 chars for each of user/group/other. + * "x-xx" instead of "x-" are to make + * "idx > 3" check catch invalid chars. + */ + static const char mode_chars[] ALIGN1 = "Ssx-" "Ssx-" "x-xx"; + static const unsigned short mode_mask[] ALIGN2 = { + S_ISUID, S_ISUID|S_IXUSR, S_IXUSR, 0, /* Ssx- */ + S_ISGID, S_ISGID|S_IXGRP, S_IXGRP, 0, /* Ssx- */ + S_IXOTH, 0 /* x- */ + }; + const char *q = strchrnul(mode_chars + 4*i, *e); + unsigned idx = q - (mode_chars + 4*i); + if (idx > 3) { errmsg = "mode"; goto pe_label; } - /* Adjust by -i to account for nul. */ - sct->m_mode |= mode_mask[(q - mode_chars) - i]; + sct->m_mode |= mode_mask[q - mode_chars]; + e++; } /* Now get the user/group info. */ @@ -512,6 +509,7 @@ static void check_suid(int applet_no) } goto check_need_suid; found: + /* Is this user allowed to run this applet? */ m = sct->m_mode; if (sct->m_ugid.uid == ruid) /* same uid */ @@ -519,28 +517,31 @@ static void check_suid(int applet_no) else if ((sct->m_ugid.gid == rgid) || ingroup(ruid, sct->m_ugid.gid)) /* same group / in group */ m >>= 3; - - if (!(m & S_IXOTH)) /* is x bit not set ? */ + if (!(m & S_IXOTH)) /* is x bit not set? */ bb_error_msg_and_die("you have no permission to run this applet!"); - /* _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_ugid.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! */ + * like we do below, seteuid(0) can still later succeed! */ + + /* Are we directed to change gid + * (APPLET = *s* USER.GROUP or APPLET = *S* USER.GROUP)? + */ + if (sct->m_mode & S_ISGID) + rgid = sct->m_ugid.gid; + /* else: we will set egid = rgid, thus dropping sgid effect */ if (setresgid(-1, rgid, rgid)) bb_perror_msg_and_die("setresgid"); - /* do we have to set effective uid? */ + /* Are we directed to change uid + * (APPLET = s** USER.GROUP or APPLET = S** USER.GROUP)? + */ uid = ruid; if (sct->m_mode & S_ISUID) uid = sct->m_ugid.uid; - /* else (no seteuid) we will set euid = ruid */ - + /* else: we will set euid = ruid, thus dropping suid effect */ if (setresuid(-1, uid, uid)) bb_perror_msg_and_die("setresuid"); + goto ret; } # if !ENABLE_FEATURE_SUID_CONFIG_QUIET |