diff options
| author | Adrian Ratiu <adrian.ratiu@collabora.com> | 2024-08-02 11:02:25 +0300 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-08-30 09:19:43 +0300 |
| commit | 41e8149c8892ed1962bd15350b3c3e6e90cba7f4 (patch) | |
| tree | debdee03fa36219472e8e53430558b82060789e2 /security | |
| parent | 8400291e289ee6b2bf9779ff1c83a291501f017b (diff) | |
| download | linux-41e8149c8892ed1962bd15350b3c3e6e90cba7f4.tar.xz | |
proc: add config & param to block forcing mem writes
This adds a Kconfig option and boot param to allow removing
the FOLL_FORCE flag from /proc/pid/mem write calls because
it can be abused.
The traditional forcing behavior is kept as default because
it can break GDB and some other use cases.
Previously we tried a more sophisticated approach allowing
distributions to fine-tune /proc/pid/mem behavior, however
that got NAK-ed by Linus [1], who prefers this simpler
approach with semantics also easier to understand for users.
Link: https://lore.kernel.org/lkml/CAHk-=wiGWLChxYmUA5HrT5aopZrB7_2VTa0NLZcxORgkUe5tEQ@mail.gmail.com/ [1]
Cc: Doug Anderson <dianders@chromium.org>
Cc: Jeff Xu <jeffxu@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Adrian Ratiu <adrian.ratiu@collabora.com>
Link: https://lore.kernel.org/r/20240802080225.89408-1-adrian.ratiu@collabora.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/Kconfig | 32 |
1 files changed, 32 insertions, 0 deletions
diff --git a/security/Kconfig b/security/Kconfig index 412e76f1575d..a93c1a9b7c28 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -19,6 +19,38 @@ config SECURITY_DMESG_RESTRICT If you are unsure how to answer this question, answer N. +choice + prompt "Allow /proc/pid/mem access override" + default PROC_MEM_ALWAYS_FORCE + help + Traditionally /proc/pid/mem allows users to override memory + permissions for users like ptrace, assuming they have ptrace + capability. + + This allows people to limit that - either never override, or + require actual active ptrace attachment. + + Defaults to the traditional behavior (for now) + +config PROC_MEM_ALWAYS_FORCE + bool "Traditional /proc/pid/mem behavior" + help + This allows /proc/pid/mem accesses to override memory mapping + permissions if you have ptrace access rights. + +config PROC_MEM_FORCE_PTRACE + bool "Require active ptrace() use for access override" + help + This allows /proc/pid/mem accesses to override memory mapping + permissions for active ptracers like gdb. + +config PROC_MEM_NO_FORCE + bool "Never" + help + Never override memory mapping permissions + +endchoice + config SECURITY bool "Enable different security models" depends on SYSFS |