mirror of
https://github.com/Droid-Deck/DroidDeck.git
synced 2026-11-11 02:51:10 +00:00
83 lines
2.8 KiB
Diff
83 lines
2.8 KiB
Diff
From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
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From: DroidDeck <noreply@droiddeck.invalid>
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Date: Tue, 20 Oct 2026 12:00:00 -0400
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Subject: [PATCH] syscall: work around Android's denial of executable stacks
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SELinux denies apps the execstack permission, so the mprotect with
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which ld.so makes the main stack executable for an object whose
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PT_GNU_STACK asks for it fails with EACCES, and the program does not
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start ("cannot enable executable stack as shared object requires:
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Permission denied", libQt5Gui.so.5 in ONLYOFFICE's Flatpak). The
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filter traces mprotect only for that exact request, and a denied one
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answers success: the stack stays non-executable, as Android keeps it.
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---
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diff --git a/src/syscall/exit.c b/src/syscall/exit.c
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index e87b7e1..71b36f5 100644
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--- a/src/syscall/exit.c
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+++ b/src/syscall/exit.c
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@@ -25,6 +25,7 @@
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#include <linux/net.h> /* SYS_*, */
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#include <linux/ioctl.h> /* _IOW, */
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#include <string.h> /* strlen(3), */
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+#include <sys/mman.h> /* PROT_*, */
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#include "cli/note.h"
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#include "syscall/syscall.h"
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@@ -552,6 +553,13 @@ void translate_syscall_exit(Tracee *tracee)
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if ((int) syscall_result == -EACCES)
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poke_reg(tracee, SYSARG_RESULT, -EPERM);
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goto end;
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+
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+ case PR_mprotect:
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+ if ((int) syscall_result == -EACCES
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+ && (peek_reg(tracee, ORIGINAL, SYSARG_3) & (PROT_EXEC | PROT_GROWSDOWN))
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+ == (PROT_EXEC | PROT_GROWSDOWN))
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+ poke_reg(tracee, SYSARG_RESULT, 0);
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+ goto end;
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#endif
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case PR_ioctl:
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diff --git a/src/syscall/seccomp.c b/src/syscall/seccomp.c
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index d9be7b4..fca220b 100644
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--- a/src/syscall/seccomp.c
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+++ b/src/syscall/seccomp.c
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@@ -46,6 +46,7 @@
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#include <asm/termbits.h>
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#include <linux/fs.h>
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#include <assert.h> /* assert(3), */
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+#include <sys/mman.h> /* PROT_*, */
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#include "syscall/seccomp.h"
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#include "tracee/tracee.h"
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@@ -316,6 +317,10 @@ static size_t trace_length_raw(Sysnum sysnum)
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return LENGTH_TRACE_PRLIMIT_STACK;
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case PR_ioctl:
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return LENGTH_TRACE_IOCTL;
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+#ifdef __ANDROID__
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+ case PR_mprotect:
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+ return LENGTH_TRACE_SYSCALL_IF_ARG;
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+#endif
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default:
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return LENGTH_TRACE_SYSCALL;
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}
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@@ -335,6 +340,11 @@ static int add_trace(struct sock_fprog *program, Sysnum sysnum, word_t syscall,
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return add_trace_prlimit_stack(program, syscall, flag);
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case PR_ioctl:
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return add_trace_ioctl_requests(program, syscall, flag);
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+#ifdef __ANDROID__
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+ case PR_mprotect:
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+ return add_trace_syscall_if_arg(program, syscall, 2,
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+ PROT_READ | PROT_WRITE | PROT_EXEC | PROT_GROWSDOWN, flag);
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+#endif
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default:
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return add_trace_syscall(program, syscall, flag);
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}
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@@ -599,6 +609,7 @@ static FilteredSysnum proot_sysnums[] = {
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{ PR_lstat64, 0 },
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#ifdef __ANDROID__
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{ PR_memfd_create, 0 },
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+ { PR_mprotect, FILTER_SYSEXIT },
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#endif
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{ PR_mkdir, 0 },
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{ PR_mkdirat, 0 },
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