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From af945ff58a698ce00c45059a05994ef53a13e192 Mon Sep 17 00:00:00 2001
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From: Jakub Filak <jfilak@redhat.com>
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Date: Fri, 17 Apr 2015 14:36:45 +0200
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Subject: [ABRT PATCH] ccpp: do not override existing files by compat cores
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Implement all checks used in kernel's do_coredump() and require
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non-relative path if suid_dumpable is 2.
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Related: #1212818
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Signed-off-by: Jakub Filak <jfilak@redhat.com>
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---
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src/hooks/abrt-hook-ccpp.c | 20 ++++++++++++++++----
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1 file changed, 16 insertions(+), 4 deletions(-)
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diff --git a/src/hooks/abrt-hook-ccpp.c b/src/hooks/abrt-hook-ccpp.c
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index 85e0d35..82ff555 100644
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--- a/src/hooks/abrt-hook-ccpp.c
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+++ b/src/hooks/abrt-hook-ccpp.c
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@@ -24,6 +24,8 @@
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#define DUMP_SUID_UNSAFE 1
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#define DUMP_SUID_SAFE 2
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+static int g_user_core_flags;
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+static int g_need_nonrelative;
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/* I want to use -Werror, but gcc-4.4 throws a curveball:
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* "warning: ignoring return value of 'ftruncate', declared with attribute warn_unused_result"
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@@ -337,7 +339,14 @@ static int open_user_core(uid_t uid, uid_t fsuid, pid_t pid, char **percent_valu
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full_core_basename = core_basename;
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if (core_basename[0] != '/')
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+ {
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+ if (g_need_nonrelative)
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+ {
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+ error_msg("Current suid_dumpable policy prevents from saving core dumps according to relative core_pattern");
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+ return -1;
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+ }
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core_basename = concat_path_file(user_pwd, core_basename);
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+ }
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/* Open (create) compat core file.
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* man core:
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@@ -372,19 +381,19 @@ static int open_user_core(uid_t uid, uid_t fsuid, pid_t pid, char **percent_valu
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struct stat sb;
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errno = 0;
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/* Do not O_TRUNC: if later checks fail, we do not want to have file already modified here */
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- int user_core_fd = open(core_basename, O_WRONLY | O_CREAT | O_NOFOLLOW, 0600); /* kernel makes 0600 too */
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+ int user_core_fd = open(core_basename, O_WRONLY | O_CREAT | O_NOFOLLOW | g_user_core_flags, 0600); /* kernel makes 0600 too */
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xsetegid(0);
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xseteuid(0);
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if (user_core_fd < 0
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|| fstat(user_core_fd, &sb) != 0
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|| !S_ISREG(sb.st_mode)
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|| sb.st_nlink != 1
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- /* kernel internal dumper checks this too: if (inode->i_uid != current->fsuid) <fail>, need to mimic? */
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+ || sb.st_uid != fsuid
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) {
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if (user_core_fd < 0)
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perror_msg("Can't open '%s'", full_core_basename);
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else
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- perror_msg("'%s' is not a regular file with link count 1", full_core_basename);
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+ perror_msg("'%s' is not a regular file with link count 1 owned by UID(%d)", full_core_basename, fsuid);
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return -1;
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}
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if (ftruncate(user_core_fd, 0) != 0) {
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@@ -578,8 +587,11 @@ int main(int argc, char** argv)
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/* use root for suided apps unless it's explicitly set to UNSAFE */
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fsuid = 0;
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if (suid_policy == DUMP_SUID_UNSAFE)
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- {
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fsuid = tmp_fsuid;
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+ else
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+ {
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+ g_user_core_flags = O_EXCL;
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+ g_need_nonrelative = 1;
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}
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}
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--
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1.8.3.1
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