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[98.147.55.211]) by smtp.gmail.com with ESMTPSA id h26-20020aa786da000000b006e555d40951sm533465pfo.188.2024.02.27.10.48.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Feb 2024 10:48:48 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: alex.bennee@linaro.org Subject: [PATCH 09/14] linux-user/elfload: Size corefile before opening Date: Tue, 27 Feb 2024 08:48:28 -1000 Message-Id: <20240227184833.193836-10-richard.henderson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240227184833.193836-1-richard.henderson@linaro.org> References: <20240227184833.193836-1-richard.henderson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2607:f8b0:4864:20::22a; envelope-from=richard.henderson@linaro.org; helo=mail-oi1-x22a.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Verify the size of the corefile vs the rlimit before opening and creating the core file at all. Signed-off-by: Richard Henderson --- linux-user/elfload.c | 83 +++++++++++++++++++++++--------------------- 1 file changed, 44 insertions(+), 39 deletions(-) diff --git a/linux-user/elfload.c b/linux-user/elfload.c index 6f9da721d7..bad01bd2ef 100644 --- a/linux-user/elfload.c +++ b/linux-user/elfload.c @@ -4270,6 +4270,16 @@ static int vma_walker(void *priv, target_ulong start, target_ulong end, return (0); } +static size_t size_note(const char *name, size_t datasz) +{ + size_t namesz = strlen(name) + 1; + + namesz = ROUND_UP(namesz, 4); + datasz = ROUND_UP(datasz, 4); + + return sizeof(struct elf_note) + namesz + datasz; +} + static void fill_note(struct memelfnote *note, const char *name, int type, unsigned int sz, void *data) { @@ -4428,27 +4438,9 @@ static int dump_write(int fd, const void *ptr, size_t size) { const char *bufp = (const char *)ptr; ssize_t bytes_written, bytes_left; - struct rlimit dumpsize; - off_t pos; bytes_written = 0; - getrlimit(RLIMIT_CORE, &dumpsize); - if ((pos = lseek(fd, 0, SEEK_CUR))==-1) { - if (errno == ESPIPE) { /* not a seekable stream */ - bytes_left = size; - } else { - return pos; - } - } else { - if (dumpsize.rlim_cur <= pos) { - return -1; - } else if (dumpsize.rlim_cur == RLIM_INFINITY) { - bytes_left = size; - } else { - size_t limit_left=dumpsize.rlim_cur - pos; - bytes_left = limit_left >= size ? size : limit_left ; - } - } + bytes_left = size; /* * In normal conditions, single write(2) should do but @@ -4622,16 +4614,15 @@ static int elf_core_dump(int signr, const CPUArchState *env) { const CPUState *cpu = env_cpu((CPUArchState *)env); const TaskState *ts = (const TaskState *)cpu->opaque; - struct vm_area_struct *vma = NULL; + struct vm_area_struct *vma; struct elf_note_info info; struct elfhdr elf; struct elf_phdr phdr; struct rlimit dumpsize; struct mm_struct mm; - off_t offset = 0, data_offset = 0; - int segs = 0; + off_t offset, note_offset, data_offset; + int segs, cpus, ret; int fd = -1; - int ret; if (prctl(PR_GET_DUMPABLE) == 0) { return 0; @@ -4646,10 +4637,36 @@ static int elf_core_dump(int signr, const CPUArchState *env) /* * Walk through target process memory mappings and - * set up structure containing this information. After - * this point vma_xxx functions can be used. + * set up structure containing this information. */ vma_init(&mm); + walk_memory_regions(&mm, vma_walker); + segs = vma_get_mapping_count(&mm); + + cpus = 0; + CPU_FOREACH(cpu) { + cpus++; + } + + offset = sizeof(struct elfhdr); + offset += (segs + 1) * sizeof(struct elf_phdr); + note_offset = offset; + + offset += size_note("CORE", ts->info->auxv_len); + offset += size_note("CORE", sizeof(struct target_elf_prpsinfo)); + offset += size_note("CORE", sizeof(struct target_elf_prstatus)) * cpus; + offset = ROUND_UP(offset, ELF_EXEC_PAGESIZE); + data_offset = offset; + + for (vma = vma_first(&mm); vma != NULL; vma = vma_next(vma)) { + offset += vma_dump_size(vma); + } + + /* Do not dump if the corefile size exceeds the limit. */ + if (dumpsize.rlim_cur != RLIM_INFINITY && dumpsize.rlim_cur < offset) { + errno = 0; + goto out; + } { g_autofree char *corefile = core_dump_filename(ts); @@ -4660,9 +4677,6 @@ static int elf_core_dump(int signr, const CPUArchState *env) goto out; } - walk_memory_regions(&mm, vma_walker); - segs = vma_get_mapping_count(&mm); - /* * Construct valid coredump ELF header. We also * add one more segment for notes. @@ -4674,26 +4688,17 @@ static int elf_core_dump(int signr, const CPUArchState *env) /* fill in the in-memory version of notes */ fill_note_info(&info, signr, env); - offset += sizeof (elf); /* elf header */ - offset += (segs + 1) * sizeof (struct elf_phdr); /* program headers */ - /* write out notes program header */ - fill_elf_note_phdr(&phdr, info.notes_size, offset); + fill_elf_note_phdr(&phdr, info.notes_size, note_offset); - offset += info.notes_size; if (dump_write(fd, &phdr, sizeof (phdr)) != 0) goto out; - /* - * ELF specification wants data to start at page boundary so - * we align it here. - */ - data_offset = offset = roundup(offset, ELF_EXEC_PAGESIZE); - /* * Write program headers for memory regions mapped in * the target process. */ + offset = data_offset; for (vma = vma_first(&mm); vma != NULL; vma = vma_next(vma)) { (void) memset(&phdr, 0, sizeof (phdr)); -- 2.34.1