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-rw-r--r--fs/exec.c23
-rw-r--r--fs/proc/base.c6
2 files changed, 25 insertions, 4 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 3a4b35a14c0..48871917d36 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -58,6 +58,9 @@
int core_uses_pid;
char core_pattern[65] = "core";
+int suid_dumpable = 0;
+
+EXPORT_SYMBOL(suid_dumpable);
/* The maximal length of core_pattern is also specified in sysctl.c */
static struct linux_binfmt *formats;
@@ -864,6 +867,9 @@ int flush_old_exec(struct linux_binprm * bprm)
if (current->euid == current->uid && current->egid == current->gid)
current->mm->dumpable = 1;
+ else
+ current->mm->dumpable = suid_dumpable;
+
name = bprm->filename;
/* Copies the binary name from after last slash */
@@ -884,7 +890,7 @@ int flush_old_exec(struct linux_binprm * bprm)
permission(bprm->file->f_dentry->d_inode,MAY_READ, NULL) ||
(bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)) {
suid_keys(current);
- current->mm->dumpable = 0;
+ current->mm->dumpable = suid_dumpable;
}
/* An exec changes our domain. We are no longer part of the thread
@@ -1432,6 +1438,8 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
struct inode * inode;
struct file * file;
int retval = 0;
+ int fsuid = current->fsuid;
+ int flag = 0;
binfmt = current->binfmt;
if (!binfmt || !binfmt->core_dump)
@@ -1441,6 +1449,16 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
up_write(&mm->mmap_sem);
goto fail;
}
+
+ /*
+ * We cannot trust fsuid as being the "true" uid of the
+ * process nor do we know its entire history. We only know it
+ * was tainted so we dump it as root in mode 2.
+ */
+ if (mm->dumpable == 2) { /* Setuid core dump mode */
+ flag = O_EXCL; /* Stop rewrite attacks */
+ current->fsuid = 0; /* Dump root private */
+ }
mm->dumpable = 0;
init_completion(&mm->core_done);
spin_lock_irq(&current->sighand->siglock);
@@ -1466,7 +1484,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
lock_kernel();
format_corename(corename, core_pattern, signr);
unlock_kernel();
- file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE, 0600);
+ file = filp_open(corename, O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, 0600);
if (IS_ERR(file))
goto fail_unlock;
inode = file->f_dentry->d_inode;
@@ -1491,6 +1509,7 @@ int do_coredump(long signr, int exit_code, struct pt_regs * regs)
close_fail:
filp_close(file, NULL);
fail_unlock:
+ current->fsuid = fsuid;
complete_all(&mm->core_done);
fail:
return retval;
diff --git a/fs/proc/base.c b/fs/proc/base.c
index e31903aadd9..ace151fa487 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -314,7 +314,7 @@ static int may_ptrace_attach(struct task_struct *task)
(current->gid != task->gid)) && !capable(CAP_SYS_PTRACE))
goto out;
rmb();
- if (!task->mm->dumpable && !capable(CAP_SYS_PTRACE))
+ if (task->mm->dumpable != 1 && !capable(CAP_SYS_PTRACE))
goto out;
if (security_ptrace(current, task))
goto out;
@@ -1113,7 +1113,9 @@ static int task_dumpable(struct task_struct *task)
if (mm)
dumpable = mm->dumpable;
task_unlock(task);
- return dumpable;
+ if(dumpable == 1)
+ return 1;
+ return 0;
}