Merge "init: improve mmap ASLR failure reporting" (b27026f9) · Commits · e / os / android_system_core

init/init.cpp

+18 −4

Original line number	Diff line number	Diff line
		@@ -310,6 +310,7 @@ static bool __attribute__((unused)) set_mmap_rnd_bits_min(int start, int min, bo
		}
		std::ifstream inf(path, std::fstream::in);
		if (!inf) {
		ERROR("Cannot open for reading: %s!\n", path.c_str());
		return false;
		}
		while (start >= min) {
		@@ -317,6 +318,7 @@ static bool __attribute__((unused)) set_mmap_rnd_bits_min(int start, int min, bo
		std::string str_val = std::to_string(start);
		std::ofstream of(path, std::fstream::out);
		if (!of) {
		ERROR("Cannot open for writing: %s!\n", path.c_str());
		return false;
		}
		of << str_val << std::endl;
		@@ -332,15 +334,27 @@ static bool __attribute__((unused)) set_mmap_rnd_bits_min(int start, int min, bo
		start--;
		}
		inf.close();
		return (start >= min);
		if (start < min) {
		ERROR("Unable to set minimum required entropy %d in %s!\n",
		min, path.c_str());
		return false;
		}
		return true;
		}

		/*
		* Set /proc/sys/vm/mmap_rnd_bits and potentially
		* /proc/sys/vm/mmap_rnd_compat_bits to the maximum supported values.
		* Returns -1 if unable to set these to an acceptable value. Apply
		* upstream patch-sets https://lkml.org/lkml/2015/12/21/337 and
		* https://lkml.org/lkml/2016/2/4/831 to enable this.
		* Returns -1 if unable to set these to an acceptable value.
		*
		* To support this sysctl, the following upstream commits are needed:
		*
		* d07e22597d1d mm: mmap: add new /proc tunable for mmap_base ASLR
		* e0c25d958f78 arm: mm: support ARCH_MMAP_RND_BITS
		* 8f0d3aa9de57 arm64: mm: support ARCH_MMAP_RND_BITS
		* 9e08f57d684a x86: mm: support ARCH_MMAP_RND_BITS
		* ec9ee4acd97c drivers: char: random: add get_random_long()
		* 5ef11c35ce86 mm: ASLR: use get_random_long()
		*/
		static int set_mmap_rnd_bits_action(const std::vector<std::string>& args)
		{