diff options
Diffstat (limited to 'debian/patches/user-group-modes.patch')
| -rw-r--r-- | debian/patches/user-group-modes.patch | 210 |
1 files changed, 210 insertions, 0 deletions
diff --git a/debian/patches/user-group-modes.patch b/debian/patches/user-group-modes.patch new file mode 100644 index 0000000..42d5b18 --- /dev/null +++ b/debian/patches/user-group-modes.patch @@ -0,0 +1,210 @@ +From 44f9b28b1c8adaf00af6e011928141cfbd729b9a Mon Sep 17 00:00:00 2001 +From: Colin Watson <cjwatson@debian.org> +Date: Sun, 9 Feb 2014 16:09:58 +0000 +Subject: Allow harmless group-writability + +Allow secure files (~/.ssh/config, ~/.ssh/authorized_keys, etc.) to be +group-writable, provided that the group in question contains only the file's +owner. Rejected upstream for IMO incorrect reasons (e.g. a misunderstanding +about the contents of gr->gr_mem). Given that per-user groups and umask 002 +are the default setup in Debian (for good reasons - this makes operating in +setgid directories with other groups much easier), we need to permit this by +default. + +Bug: https://bugzilla.mindrot.org/show_bug.cgi?id=1060 +Bug-Debian: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=314347 +Last-Update: 2022-02-23 + +Patch-Name: user-group-modes.patch +--- + auth-rhosts.c | 6 ++---- + auth.c | 3 +-- + misc.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++----- + misc.h | 2 ++ + readconf.c | 3 +-- + ssh.1 | 2 ++ + ssh_config.5 | 2 ++ + 7 files changed, 62 insertions(+), 13 deletions(-) + +diff --git a/auth-rhosts.c b/auth-rhosts.c +index 56724677a..e15f5bc5a 100644 +--- a/auth-rhosts.c ++++ b/auth-rhosts.c +@@ -266,8 +266,7 @@ auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname, + return 0; + } + if (options.strict_modes && +- ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || +- (st.st_mode & 022) != 0)) { ++ !secure_permissions(&st, pw->pw_uid)) { + logit("Rhosts authentication refused for %.100s: " + "bad ownership or modes for home directory.", pw->pw_name); + auth_debug_add("Rhosts authentication refused for %.100s: " +@@ -296,8 +295,7 @@ auth_rhosts2(struct passwd *pw, const char *client_user, const char *hostname, + * allowing access to their account by anyone. + */ + if (options.strict_modes && +- ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || +- (st.st_mode & 022) != 0)) { ++ !secure_permissions(&st, pw->pw_uid)) { + logit("Rhosts authentication refused for %.100s: " + "bad modes for %.200s", pw->pw_name, path); + auth_debug_add("Bad file modes for %.200s", path); +diff --git a/auth.c b/auth.c +index 8ccf06370..08a75fc4e 100644 +--- a/auth.c ++++ b/auth.c +@@ -431,8 +431,7 @@ check_key_in_hostfiles(struct passwd *pw, struct sshkey *key, const char *host, + user_hostfile = tilde_expand_filename(userfile, pw->pw_uid); + if (options.strict_modes && + (stat(user_hostfile, &st) == 0) && +- ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || +- (st.st_mode & 022) != 0)) { ++ !secure_permissions(&st, pw->pw_uid)) { + logit("Authentication refused for %.100s: " + "bad owner or modes for %.200s", + pw->pw_name, user_hostfile); +diff --git a/misc.c b/misc.c +index 3db2e4d0b..f667a99f8 100644 +--- a/misc.c ++++ b/misc.c +@@ -62,9 +62,9 @@ + #include <netdb.h> + #ifdef HAVE_PATHS_H + # include <paths.h> ++#endif + #include <pwd.h> + #include <grp.h> +-#endif + #ifdef SSH_TUN_OPENBSD + #include <net/if.h> + #endif +@@ -1414,6 +1414,55 @@ percent_dollar_expand(const char *string, ...) + return ret; + } + ++int ++secure_permissions(struct stat *st, uid_t uid) ++{ ++ if (!platform_sys_dir_uid(st->st_uid) && st->st_uid != uid) ++ return 0; ++ if ((st->st_mode & 002) != 0) ++ return 0; ++ if ((st->st_mode & 020) != 0) { ++ /* If the file is group-writable, the group in question must ++ * have exactly one member, namely the file's owner. ++ * (Zero-member groups are typically used by setgid ++ * binaries, and are unlikely to be suitable.) ++ */ ++ struct passwd *pw; ++ struct group *gr; ++ int members = 0; ++ ++ gr = getgrgid(st->st_gid); ++ if (!gr) ++ return 0; ++ ++ /* Check primary group memberships. */ ++ while ((pw = getpwent()) != NULL) { ++ if (pw->pw_gid == gr->gr_gid) { ++ ++members; ++ if (pw->pw_uid != uid) ++ return 0; ++ } ++ } ++ endpwent(); ++ ++ pw = getpwuid(st->st_uid); ++ if (!pw) ++ return 0; ++ ++ /* Check supplementary group memberships. */ ++ if (gr->gr_mem[0]) { ++ ++members; ++ if (strcmp(pw->pw_name, gr->gr_mem[0]) || ++ gr->gr_mem[1]) ++ return 0; ++ } ++ ++ if (!members) ++ return 0; ++ } ++ return 1; ++} ++ + int + tun_open(int tun, int mode, char **ifname) + { +@@ -2223,8 +2272,7 @@ safe_path(const char *name, struct stat *stp, const char *pw_dir, + snprintf(err, errlen, "%s is not a regular file", buf); + return -1; + } +- if ((!platform_sys_dir_uid(stp->st_uid) && stp->st_uid != uid) || +- (stp->st_mode & 022) != 0) { ++ if (!secure_permissions(stp, uid)) { + snprintf(err, errlen, "bad ownership or modes for file %s", + buf); + return -1; +@@ -2239,8 +2287,7 @@ safe_path(const char *name, struct stat *stp, const char *pw_dir, + strlcpy(buf, cp, sizeof(buf)); + + if (stat(buf, &st) == -1 || +- (!platform_sys_dir_uid(st.st_uid) && st.st_uid != uid) || +- (st.st_mode & 022) != 0) { ++ !secure_permissions(&st, uid)) { + snprintf(err, errlen, + "bad ownership or modes for directory %s", buf); + return -1; +diff --git a/misc.h b/misc.h +index 74c6f832c..0aabe84ad 100644 +--- a/misc.h ++++ b/misc.h +@@ -237,6 +237,8 @@ struct notifier_ctx *notify_start(int, const char *, ...) + void notify_complete(struct notifier_ctx *, const char *, ...) + __attribute__((format(printf, 2, 3))); + ++int secure_permissions(struct stat *st, uid_t uid); ++ + #define MINIMUM(a, b) (((a) < (b)) ? (a) : (b)) + #define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b)) + #define ROUNDUP(x, y) ((((x)+((y)-1))/(y))*(y)) +diff --git a/readconf.c b/readconf.c +index bd2e78ab7..6cf3612e7 100644 +--- a/readconf.c ++++ b/readconf.c +@@ -2481,8 +2481,7 @@ read_config_file_depth(const char *filename, struct passwd *pw, + + if (fstat(fileno(f), &sb) == -1) + fatal("fstat %s: %s", filename, strerror(errno)); +- if (((sb.st_uid != 0 && sb.st_uid != getuid()) || +- (sb.st_mode & 022) != 0)) ++ if (!secure_permissions(&sb, getuid())) + fatal("Bad owner or permissions on %s", filename); + } + +diff --git a/ssh.1 b/ssh.1 +index 877c3bc64..2d07c919e 100644 +--- a/ssh.1 ++++ b/ssh.1 +@@ -1577,6 +1577,8 @@ The file format and configuration options are described in + .Xr ssh_config 5 . + Because of the potential for abuse, this file must have strict permissions: + read/write for the user, and not writable by others. ++It may be group-writable provided that the group in question contains only ++the user. + .Pp + .It Pa ~/.ssh/environment + Contains additional definitions for environment variables; see +diff --git a/ssh_config.5 b/ssh_config.5 +index 25ccbed28..bebfe1cee 100644 +--- a/ssh_config.5 ++++ b/ssh_config.5 +@@ -2395,6 +2395,8 @@ The format of this file is described above. + This file is used by the SSH client. + Because of the potential for abuse, this file must have strict permissions: + read/write for the user, and not writable by others. ++It may be group-writable provided that the group in question contains only ++the user. + .It Pa /etc/ssh/ssh_config + Systemwide configuration file. + This file provides defaults for those |