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[130.117.225.111]) by mx.google.com with ESMTPS id ffacd0b85a97d-48de0bf17c0si12780710f8f.293.2026.10.14.10.15.05 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Oct 2026 10:15:05 -0700 (PDT) Received-SPF: pass (google.com: domain of khorenko@virtuozzo.com designates 130.117.225.111 as permitted sender) client-ip=130.117.225.111; Authentication-Results: mx.google.com; dkim=pass header.i=@virtuozzo.com header.s=relay header.b=h2ERL9R5; spf=pass (google.com: domain of khorenko@virtuozzo.com designates 130.117.225.111 as permitted sender) smtp.mailfrom=khorenko@virtuozzo.com; dmarc=pass (p=QUARANTINE sp=QUARANTINE dis=NONE) header.from=virtuozzo.com DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=virtuozzo.com; s=relay; h=Message-Id:Content-Type:MIME-Version:Subject:Date :From; bh=hDF7P/lu8hCh+KLPGUmHkPjtGT8GmsLERkyXWZIFRjo=; b=h2ERL9R5mS9mgFl7Cdy ul2LdCm+CEn0YCrjJ7ES8b6d/GOAGWvnUFiLUXeQqpbBUbwHqBX2ps2SMvY6WEVC2OYuUEQ8Zi3m+ so81yy0Kwi3c51JZxX/MeThwmmx6qowMKMTP/8O8XdF/+EtirQzkMFw/xPvKjkjiAxOfDc9xhqm1S l12VtOCgfSlj3ydYiFVNei16Iq2IDZ05ES5dqtl8QZay/Bd1ty+C03gpIkPwHtPC8AblcBXkcXOvc 5HNoM25UZhqqA3SwedT1SXxrP4Hkm8guiA7UEwWh+ZbwS4oboPQfgL/YQu3tEhF2NakOy/Yf6eBEy CuvGDI5wGlAQJxA==; Received: from ch-demo-asa.virtuozzo.com ([130.117.225.8] helo=f0.sw.ru) by relay.virtuozzo.com with esmtp (Exim 4.96) (envelope-from ) id 1xH2Vo-008657-0v; Wed, 14 Oct 2026 19:15:04 +0200 From: Konstantin Khorenko Date: Wed, 14 Oct 2026 19:15:03 +0200 MIME-Version: 1.0 Message-Id: <20261014-b4-prep-khorenko-vstor-149847-5-doexec-selftests-v1-5-b23b454691db@virtuozzo.com> References: <20261014-b4-prep-khorenko-vstor-149847-5-doexec-selftests-v1-0-b23b454691db@virtuozzo.com> In-Reply-To: <20261014-b4-prep-khorenko-vstor-149847-5-doexec-selftests-v1-0-b23b454691db@virtuozzo.com> To: Pavel Tikhomirov , Andrey Drobyshev , Vasileios Almpanis X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=4927; i=khorenko@virtuozzo.com; h=from:subject:message-id; bh=zT7xsBE9PLmXsp3Lr9R9LwAbjVTXgDGGUDSjl8SPSjk=; b=owEBbQKS/ZANAwAKAVGWCkf5YVwqAcsmYgBqz7iXHRMXUWrI4o16b67s3v/siCxOTkL4FGzTF vWfoP2sDFGJAjMEAAEKAB0WIQRWD23IPcXT0GO9CCxRlgpH+WFcKgUCas+4lwAKCRBRlgpH+WFc KhzCD/46VXv5dSzsBOeYQFUO6tVq+6ZVpE618ijDFhdwfZSXbENcY3p5VZkBczUmlk2jpmIwG4j aLDHfL7vVMdWfpzGCxliv9PqddC5UcfiUB73avxYdFkUnEWyp+qmKcRn+p4lEsdSv/3sBdONLTZ K7L6QG+oEEUpLTil1xzC0H6UWrEG+tqsT0SNNdXRrfHcQjZ++ygnN48XMraroIl0q9wc2VvcgqP X0lVIC8om8NldADS+88VKv0PGxdwVEO+zNAeLM0ztPid6vwEr7WlZVNwDWO1wFHHn5c5vMee3qb 4IOhyqx5M9iNhV5H+HR7bjiP3o3GrVHm+sN4rtthYOm48OERsKgdFLTUb0Hrlh6o394AUevwegI PBJTe0QaQx9H+flAsO8RI5Xlr3cVE25AGbAeaQ0MzZxgRTkPoLVCUQgks8cYW4655+9x62yh/lf isMVU2jSGY3Tiiq3zD9lF7h03LGEOvfyfzGVufnxZgZ5jKz3iRvWptwD9hgMHlsr+gAAmvteTvl 1EqXBon0+MmZDuGfx9kIQSnNuu6+E9NAXEqB+Jo+HnCh9wyTdHvLX/rJzcFENxlc4/deMDmIcW6 4etCLPLjIotqTvkeoBniT9uytIf1ysWXgZh66NqO1OMV0KW3FMvx16w2C69+2jGHegWNxf+88is dA1qAPeSRWS3Hlg== X-Developer-Key: i=khorenko@virtuozzo.com; a=openpgp; fpr=560F6DC83DC5D3D063BD082C51960A47F9615C2A X-OZ-Fwd: true Cc: devel@openvz.org Subject: [Devel] [PATCH hci-8.1 5/7] selftests/mm: check VM_MAYEXEC of MADV_DOEXEC ranges in smaps X-BeenThere: devel@openvz.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: OpenVZ development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: devel-bounces@openvz.org Errors-To: devel-bounces@openvz.org An EACCES from mprotect(PROT_EXEC) does not prove that VM_MAYEXEC is clear: an LSM or MDWE refuses it the same way. Read the flag from VmFlags as well. Also check that a fork child and the new image get VM_MAYEXEC back, as the mark is dropped from their copies. https://virtuozzo.atlassian.net/browse/VSTOR-150234 Feature: oracle/mm: MADV_DOEXEC madvise() flag Assisted-by: LLM Signed-off-by: Konstantin Khorenko --- tools/testing/selftests/mm/doexec.c | 94 +++++++++++++++++++++++++------------ 1 file changed, 64 insertions(+), 30 deletions(-) diff --git a/tools/testing/selftests/mm/doexec.c b/tools/testing/selftests/mm/doexec.c index 01e786a4cb75c..89862e0b6a4dc 100644 --- a/tools/testing/selftests/mm/doexec.c +++ b/tools/testing/selftests/mm/doexec.c @@ -583,9 +583,43 @@ static int devzero_exec(void) return KSFT_FAIL; } +/* Copy the line of the smaps entry of the VMA at @addr that starts with @prefix. */ +static bool smaps_line(char *addr, const char *prefix, char *line, size_t len) +{ + FILE *file = fopen("/proc/self/smaps", "r"); + bool in_vma = false, found = false; + char want[32]; + + if (!file) + return false; + snprintf(want, sizeof(want), "%lx-", (unsigned long)addr); + while (!found && fgets(line, len, file)) { + char *space = strchr(line, ' '); + + if (space && memchr(line, '-', space - line) && !memchr(line, ':', space - line)) + in_vma = !strncmp(line, want, strlen(want)); + else if (in_vma) + found = !strncmp(line, prefix, strlen(prefix)); + } + fclose(file); + return found; +} + +static bool smaps_has_flag(char *addr, const char *flag) +{ + char line[512]; + + return smaps_line(addr, "VmFlags:", line, sizeof(line)) && strstr(line, flag); +} + +/* VM_MAYEXEC ("me") is clear, so mprotect(PROT_EXEC) fails. */ static bool exec_refused(char *ram, size_t size) { - return mprotect(ram, size, PROT_READ | PROT_EXEC) && errno == EACCES; + char line[512]; + + return smaps_line(ram, "VmFlags:", line, sizeof(line)) && + !strstr(line, " me ") && + mprotect(ram, size, PROT_READ | PROT_EXEC) && errno == EACCES; } /* MADV_DONTEXEC must not grant more than mmap() did on a noexec mount. */ @@ -645,35 +679,6 @@ static int doexec_noexec(void) return ret; } -/* Copy the line of the smaps entry of the VMA at @addr that starts with @prefix. */ -static bool smaps_line(char *addr, const char *prefix, char *line, size_t len) -{ - FILE *file = fopen("/proc/self/smaps", "r"); - bool in_vma = false, found = false; - char want[32]; - - if (!file) - return false; - snprintf(want, sizeof(want), "%lx-", (unsigned long)addr); - while (!found && fgets(line, len, file)) { - char *space = strchr(line, ' '); - - if (space && memchr(line, '-', space - line) && !memchr(line, ':', space - line)) - in_vma = !strncmp(line, want, strlen(want)); - else if (in_vma) - found = !strncmp(line, prefix, strlen(prefix)); - } - fclose(file); - return found; -} - -static bool smaps_has_flag(char *addr, const char *flag) -{ - char line[512]; - - return smaps_line(addr, "VmFlags:", line, sizeof(line)) && strstr(line, flag); -} - static int after_pfnmap_exec(char *bar, size_t size) { size_t page = sysconf(_SC_PAGESIZE), i; @@ -1274,6 +1279,33 @@ static int locked_exec(void) return exec_with_flag(ram, size, "--unlocked", " lo "); } +/* Dropping the mark in a copy gives VM_MAYEXEC back. */ +static int mayexec_exec(void) +{ + size_t size = sysconf(_SC_PAGESIZE); + char *ram = preserved_ram(size); + pid_t pid; + + if (!ram) + return unsupported(); + if (!exec_refused(ram, size)) + return fail("VM_MAYEXEC kept by MADV_DOEXEC"); + pid = fork(); + if (!pid) + _exit(smaps_has_flag(ram, " me ") ? KSFT_PASS : KSFT_FAIL); + if (pid < 0 || wait_child(pid) != KSFT_PASS) + return fail("VM_MAYEXEC not back in a fork child"); + exec_mode("/proc/self/exe", "--mayexec", ram, size); + return KSFT_FAIL; +} + +static int after_mayexec(char *ram, size_t size) +{ + if (!smaps_has_flag(ram, " me ")) + return fail("VM_MAYEXEC not back after exec"); + return check_contents(ram, size, 0x31); +} + static int after_unlocked(char *ram, size_t size) { if (smaps_has_flag(ram, " lo ")) @@ -1832,6 +1864,7 @@ static const struct after_mode after_modes[] = { { "--no-uffd", after_no_uffd }, { "--mempolicy", after_mempolicy }, { "--thp-half", after_thp_half }, + { "--mayexec", after_mayexec }, }; struct more_case { @@ -1886,6 +1919,7 @@ static const struct more_case more_cases[] = { { "swapped out pages: preserved", swapped_exec }, { "half of a THP: preserved", thp_half_exec }, { "vfork() child: preserving exec refused", vfork_exec }, + { "exec permission back in a fork child and the new image", mayexec_exec }, }; int main(int argc, char **argv) -- 2.43.0 _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel