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| author | Eric W. Biederman <ebiederm@xmission.com> | 2016-11-22 12:06:50 -0600 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2016-11-22 12:57:38 -0600 |
| commit | 84d77d3f06e7e8dea057d10e8ec77ad71f721be3 (patch) | |
| tree | 6efbcfc0877019c2afbdf11596362c8198ebdd0d /arch/blackfin | |
| parent | 64b875f7ac8a5d60a4e191479299e931ee949b67 (diff) | |
| download | linux-84d77d3f06e7e8dea057d10e8ec77ad71f721be3.tar.gz | |
ptrace: Don't allow accessing an undumpable mm
It is the reasonable expectation that if an executable file is not readable there will be no way for a user without special privileges to read the file. This is enforced in ptrace_attach but if ptrace is already attached before exec there is no enforcement for read-only executables. As the only way to read such an mm is through access_process_vm spin a variant called ptrace_access_vm that will fail if the target process is not being ptraced by the current process, or the current process did not have sufficient privileges when ptracing began to read the target processes mm. In the ptrace implementations replace access_process_vm by ptrace_access_vm. There remain several ptrace sites that still use access_process_vm as they are reading the target executables instructions (for kernel consumption) or register stacks. As such it does not appear necessary to add a permission check to those calls. This bug has always existed in Linux. Fixes: v1.0 Cc: stable@vger.kernel.org Reported-by: Andy Lutomirski <luto@amacapital.net> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'arch/blackfin')
| -rw-r--r-- | arch/blackfin/kernel/ptrace.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/blackfin/kernel/ptrace.c b/arch/blackfin/kernel/ptrace.c index 8d79286ee4e8..360d99645163 100644 --- a/arch/blackfin/kernel/ptrace.c +++ b/arch/blackfin/kernel/ptrace.c @@ -270,7 +270,7 @@ long arch_ptrace(struct task_struct *child, long request, switch (bfin_mem_access_type(addr, to_copy)) { case BFIN_MEM_ACCESS_CORE: case BFIN_MEM_ACCESS_CORE_ONLY: - copied = access_process_vm(child, addr, &tmp, + copied = ptrace_access_vm(child, addr, &tmp, to_copy, FOLL_FORCE); if (copied) break; @@ -323,7 +323,7 @@ long arch_ptrace(struct task_struct *child, long request, switch (bfin_mem_access_type(addr, to_copy)) { case BFIN_MEM_ACCESS_CORE: case BFIN_MEM_ACCESS_CORE_ONLY: - copied = access_process_vm(child, addr, &data, + copied = ptrace_access_vm(child, addr, &data, to_copy, FOLL_FORCE | FOLL_WRITE); break; |