X-Git-Url: https://git.kernelconcepts.de/?a=blobdiff_plain;f=fs%2Fcoredump.c;h=dfc87c5f5a54febea6f6e36bd3636965f9fa6396;hb=4dc809685c3b30c20f46886f54e4f96772328f3f;hp=1777331eee767fa323cb864fb95131983eaad588;hpb=c0d6fe2f01c475cc137d90607a07578586883df8;p=karo-tx-linux.git

diff --git a/fs/coredump.c b/fs/coredump.c
index 1777331eee76..dfc87c5f5a54 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -32,6 +32,9 @@
 #include <linux/pipe_fs_i.h>
 #include <linux/oom.h>
 #include <linux/compat.h>
+#include <linux/sched.h>
+#include <linux/fs.h>
+#include <linux/path.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -627,6 +630,8 @@ void do_coredump(const siginfo_t *siginfo)
 		}
 	} else {
 		struct inode *inode;
+		int open_flags = O_CREAT | O_RDWR | O_NOFOLLOW |
+				 O_LARGEFILE | O_EXCL;
 
 		if (cprm.limit < binfmt->min_coredump)
 			goto fail_unlock;
@@ -665,10 +670,27 @@ void do_coredump(const siginfo_t *siginfo)
 		 * what matters is that at least one of the two processes
 		 * writes its coredump successfully, not which one.
 		 */
-		cprm.file = filp_open(cn.corename,
-				 O_CREAT | 2 | O_NOFOLLOW |
-				 O_LARGEFILE | O_EXCL,
-				 0600);
+		if (need_suid_safe) {
+			/*
+			 * Using user namespaces, normal user tasks can change
+			 * their current->fs->root to point to arbitrary
+			 * directories. Since the intention of the "only dump
+			 * with a fully qualified path" rule is to control where
+			 * coredumps may be placed using root privileges,
+			 * current->fs->root must not be used. Instead, use the
+			 * root directory of init_task.
+			 */
+			struct path root;
+
+			task_lock(&init_task);
+			get_fs_root(init_task.fs, &root);
+			task_unlock(&init_task);
+			cprm.file = file_open_root(root.dentry, root.mnt,
+				cn.corename, open_flags, 0600);
+			path_put(&root);
+		} else {
+			cprm.file = filp_open(cn.corename, open_flags, 0600);
+		}
 		if (IS_ERR(cprm.file))
 			goto fail_unlock;