From: Divya Chellam Date: Mon, 9 Jun 2025 10:10:27 +0000 (+0530) Subject: screen: fix CVE-2025-46804 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=fa14b05383a322f5fe751c81e8c6f1a8a1df8c9e;p=thirdparty%2Fopenembedded%2Fopenembedded-core-contrib.git screen: fix CVE-2025-46804 A minor information leak when running Screen with setuid-root privileges allosw unprivileged users to deduce information about a path that would otherwise not be available. Affected are older Screen versions, as well as version 5.0.0. Reference: https://security-tracker.debian.org/tracker/CVE-2025-46804 Upstream-patch: https://cgit.git.savannah.gnu.org/cgit/screen.git/commit/?id=e0eef5aac453fa98a2664416a56c50ad1d00cb30 Signed-off-by: Divya Chellam Signed-off-by: Steve Sakoman --- diff --git a/meta/recipes-extended/screen/screen/CVE-2025-46804.patch b/meta/recipes-extended/screen/screen/CVE-2025-46804.patch new file mode 100644 index 0000000000..4cb1465535 --- /dev/null +++ b/meta/recipes-extended/screen/screen/CVE-2025-46804.patch @@ -0,0 +1,131 @@ +From e0eef5aac453fa98a2664416a56c50ad1d00cb30 Mon Sep 17 00:00:00 2001 +From: Matthias Gerstner +Date: Mon, 12 May 2025 15:26:11 +0200 +Subject: [PATCH] fix CVE-2025-46804: avoid file existence test information + leaks + +In setuid-root context the current error messages give away whether +certain paths not accessible by the real user exist and what type they +have. To prevent this only output generic error messages in setuid-root +context. + +In some situations, when an error is pertaining a directory and the +directory is owner by the real user then we can still output more +detailed diagnostics. + +This change can lead to less helpful error messages when Screen is +install setuid-root. More complex changes would be needed to avoid this +(e.g. only open the `SocketPath` with raised privileges when +multi-attach is requested). + +There might still be lingering some code paths that allow such +information leaks, since `SocketPath` is a global variable that is used +across the code base. The majority of issues should be caught with this +fix, however. + +CVE: CVE-2025-46804 + +Upstream-Status: Backport [https://cgit.git.savannah.gnu.org/cgit/screen.git/commit/?id=e0eef5aac453fa98a2664416a56c50ad1d00cb30] + +Signed-off-by: Divya Chellam +--- + screen.c | 45 ++++++++++++++++++++++++++++++++++----------- + socket.c | 9 +++++++-- + 2 files changed, 41 insertions(+), 13 deletions(-) + +diff --git a/screen.c b/screen.c +index f2e8171..ef6c26a 100644 +--- a/screen.c ++++ b/screen.c +@@ -1122,15 +1122,28 @@ int main(int ac, char** av) + #endif + } + +- if (stat(SockPath, &st) == -1) +- Panic(errno, "Cannot access %s", SockPath); +- else +- if (!S_ISDIR(st.st_mode)) ++ if (stat(SockPath, &st) == -1) { ++ if (eff_uid == real_uid) { ++ Panic(errno, "Cannot access %s", SockPath); ++ } else { ++ Panic(0, "Error accessing %s", SockPath); ++ } ++ } else if (!S_ISDIR(st.st_mode)) { ++ if (eff_uid == real_uid || st.st_uid == real_uid) { + Panic(0, "%s is not a directory.", SockPath); ++ } else { ++ Panic(0, "Error accessing %s", SockPath); ++ } ++ } + #ifdef MULTIUSER + if (multi) { +- if ((int)st.st_uid != multi_uid) +- Panic(0, "%s is not the owner of %s.", multi, SockPath); ++ if ((int)st.st_uid != multi_uid) { ++ if (eff_uid == real_uid || st.st_uid == real_uid) { ++ Panic(0, "%s is not the owner of %s.", multi, SockPath); ++ } else { ++ Panic(0, "Error accessing %s", SockPath); ++ } ++ } + } + else + #endif +@@ -1144,9 +1157,13 @@ int main(int ac, char** av) + Panic(0, "You are not the owner of %s.", SockPath); + #endif + } +- +- if ((st.st_mode & 0777) != 0700) +- Panic(0, "Directory %s must have mode 700.", SockPath); ++ if ((st.st_mode & 0777) != 0700) { ++ if (eff_uid == real_uid || st.st_uid == real_uid) { ++ Panic(0, "Directory %s must have mode 700.", SockPath); ++ } else { ++ Panic(0, "Error accessing %s", SockPath); ++ } ++ } + if (SockMatch && index(SockMatch, '/')) + Panic(0, "Bad session name '%s'", SockMatch); + SockName = SockPath + strlen(SockPath) + 1; +@@ -1184,8 +1201,14 @@ int main(int ac, char** av) + else + exit(9 + (fo || oth ? 1 : 0) + fo); + } +- if (fo == 0) +- Panic(0, "No Sockets found in %s.\n", SockPath); ++ if (fo == 0) { ++ if (eff_uid == real_uid || st.st_uid == real_uid) { ++ Panic(0, "No Sockets found in %s.\n", SockPath); ++ } else { ++ Panic(0, "Error accessing %s", SockPath); ++ } ++ } ++ + Msg(0, "%d Socket%s in %s.", fo, fo > 1 ? "s" : "", SockPath); + eexit(0); + } +diff --git a/socket.c b/socket.c +index 3bbd64e..5661e6e 100644 +--- a/socket.c ++++ b/socket.c +@@ -169,8 +169,13 @@ bool *is_sock; + xsetegid(real_gid); + #endif + +- if ((dirp = opendir(SockPath)) == 0) +- Panic(errno, "Cannot opendir %s", SockPath); ++ if ((dirp = opendir(SockPath)) == 0) { ++ if (eff_uid == real_uid) { ++ Panic(errno, "Cannot opendir %s", SockPath); ++ } else { ++ Panic(0, "Error accessing %s", SockPath); ++ } ++ } + + slist = 0; + slisttail = &slist; +-- +2.40.0 + diff --git a/meta/recipes-extended/screen/screen_4.9.0.bb b/meta/recipes-extended/screen/screen_4.9.0.bb index 540a78e04b..574b738dbf 100644 --- a/meta/recipes-extended/screen/screen_4.9.0.bb +++ b/meta/recipes-extended/screen/screen_4.9.0.bb @@ -24,6 +24,7 @@ SRC_URI = "${GNU_MIRROR}/screen/screen-${PV}.tar.gz \ file://CVE-2023-24626.patch \ file://CVE-2025-46805.patch \ file://CVE-2025-46802.patch \ + file://CVE-2025-46804.patch \ " SRC_URI[sha256sum] = "f9335281bb4d1538ed078df78a20c2f39d3af9a4e91c57d084271e0289c730f4"