curl_fuzzer: inject allocations and io failures

curl_fuzzer.cc

@@ -27,6 +27,8 @@
 #include <curl/curl.h>
 #include "curl_fuzzer.h"
 
+#include "nallocinc.c"
+
 /**
  * Fuzzing entry point. This function is passed a buffer containing a test
  * case.  This test case should drive the CURL API into making a request.
@@ -49,6 +51,8 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
     goto EXIT_LABEL;
   }
 
+  nalloc_init(NULL);
+  nalloc_restrict_file_prefix("/src/curl/");
   /* Try to initialize the fuzz data */
   FTRY(fuzz_initialize_fuzz_data(&fuzz, data, size));
 
@@ -93,8 +97,10 @@ extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
     curl_easy_setopt(fuzz.easy, CURLOPT_HTTPPOST, fuzz.httppost);
   }
 
+  nalloc_start(data, size);
   /* Run the transfer. */
   fuzz_handle_transfer(&fuzz);
+  nalloc_end();
 
 EXIT_LABEL:
 

nallocinc.c

@@ -0,0 +1,366 @@
+/*
+ MIT License
+
+ Copyright (c) 2025 Catena cyber
+
+ Permission is hereby granted, free of charge, to any person obtaining a copy
+ of this software and associated documentation files (the "Software"), to deal
+ in the Software without restriction, including without limitation the rights
+ to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ copies of the Software, and to permit persons to whom the Software is
+ furnished to do so, subject to the following conditions:
+
+ The above copyright notice and this permission notice shall be included in all
+ copies or substantial portions of the Software.
+
+ THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ SOFTWARE.
+*/
+
+/* Nalloc fuzz : framework to make allocations and IO fail while fuzzing */
+
+/* Environment variables to control nalloc fuzz behavior :
+ * NALLOC_VERBOSE: set it to log failed allocations with their stacktraces
+ * NALLOC_FREQ: set it to control how frequently allocations fail
+ *  value 0 disables nalloc (no allocations fail)
+ *  value 1..31 : allocations fail always (1) or very rarely (31 -> 1 / 2^31)
+ *  value 32 : allocations fail at a random rate between 5 and 20 for each run
+ */
+
+#ifndef NALLOC_INC_C_
+#define NALLOC_INC_C_
+
+#if defined(__clang__) && defined(__has_feature)
+#if __has_feature(address_sanitizer)
+#define NALLOC_ASAN 1
+#endif
+#endif
+
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+static const uint32_t nalloc_crc32_table[] = {
+    0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b,
+    0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
+    0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7,
+    0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
+    0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3,
+    0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+    0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef,
+    0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
+    0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb,
+    0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
+    0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0,
+    0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
+    0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4,
+    0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
+    0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08,
+    0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+    0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc,
+    0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
+    0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050,
+    0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
+    0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34,
+    0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
+    0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1,
+    0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
+    0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5,
+    0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+    0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9,
+    0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
+    0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd,
+    0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
+    0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71,
+    0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
+    0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2,
+    0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
+    0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e,
+    0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+    0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a,
+    0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
+    0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676,
+    0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
+    0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662,
+    0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
+    0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4};
+
+// Nallocfuzz data to take a decision
+uint32_t nalloc_random_state = 0;
+__thread unsigned int nalloc_running = 0;
+bool nalloc_initialized = false;
+uint32_t nalloc_runs = 0;
+
+// Nalloc fuzz parameters
+uint32_t nalloc_bitmask = 0xFF;
+bool nalloc_random_bitmask = true;
+uint32_t nalloc_magic = 0x294cee63;
+bool nalloc_verbose = false;
+const char * nalloc_prefix = "";
+uint32_t nalloc_prefix_len = 0;
+
+#ifdef NALLOC_ASAN
+extern void __sanitizer_print_stack_trace(void);
+extern void __sanitizer_symbolize_pc(void * pc, const char *fmt,
+                                     char *out_buf, size_t out_buf_size);
+#endif
+
+#define NALLOC_PREFIX_MAX 1024
+
+void nalloc_restrict_file_prefix(const char *prefix) {
+  if (nalloc_prefix_len < NALLOC_PREFIX_MAX) {
+    nalloc_prefix = prefix;
+    nalloc_prefix_len = (uint32_t)strlen(prefix);
+  }
+}
+
+// Generic init, using env variables to get parameters
+void nalloc_init(const char *prog) {
+  if (nalloc_initialized) {
+    return;
+  }
+  nalloc_initialized = true;
+  char *bitmask = getenv("NALLOC_FREQ");
+  if (bitmask) {
+    int shift = atoi(bitmask);
+    if (shift > 0 && shift < 31) {
+      nalloc_bitmask = 1 << shift;
+      nalloc_random_bitmask = false;
+    } else if (shift == 0) {
+      nalloc_random_bitmask = false;
+      nalloc_bitmask = 0;
+    }
+  } else if (prog == NULL || strstr(prog, "nalloc") == NULL) {
+    nalloc_random_bitmask = false;
+    nalloc_bitmask = 0;
+    return;
+  }
+
+  char *verbose = getenv("NALLOC_VERBOSE");
+  if (verbose) {
+    nalloc_verbose = true;
+  }
+  char *rfp = getenv("NALLOC_RESTRICT_FILE_PREFIX");
+  if (rfp) {
+    nalloc_restrict_file_prefix(rfp);
+  }
+}
+
+// add one byte to the CRC
+static inline void nalloc_random_update(uint8_t b) {
+  nalloc_random_state =
+      ((uint32_t)((uint32_t)nalloc_random_state << 8)) ^
+      nalloc_crc32_table[((nalloc_random_state >> 24) ^ b) & 0xFF];
+}
+
+// Start the failure injections, using a buffer as seed
+static int nalloc_start(const uint8_t *data, size_t size) {
+  if (nalloc_random_bitmask) {
+    if (nalloc_random_state & 0x10) {
+      nalloc_bitmask = 0xFFFFFFFF;
+    } else {
+      nalloc_bitmask = 1 << (5 + (nalloc_random_state & 0xF));
+    }
+  } else if (nalloc_bitmask == 0) {
+    // nalloc disabled
+    return 0;
+  }
+  nalloc_random_state = 0;
+  for (size_t i = 0; i < size; i++) {
+    nalloc_random_update(data[i]);
+  }
+  if (__sync_fetch_and_add(&nalloc_running, 1)) {
+    __sync_fetch_and_sub(&nalloc_running, 1);
+    return 0;
+  }
+  nalloc_runs++;
+  return 1;
+}
+
+#define nalloc_return_address() __builtin_return_address(1)
+
+// Stop the failure injections
+static void nalloc_end() { __sync_fetch_and_sub(&nalloc_running, 1); }
+
+__attribute__((noinline))
+static bool nalloc_backtrace_exclude(size_t size, const char *op, void *pc) {
+#ifdef NALLOC_ASAN
+  if (nalloc_prefix_len > 0) {
+    char data[NALLOC_PREFIX_MAX];
+    __sanitizer_symbolize_pc(pc, "%s", data, sizeof(data)-1);
+    for (size_t i = 0; i < nalloc_prefix_len; i++) {
+      if (data[i] != nalloc_prefix[i]) {
+        return true;
+      }
+    }
+  }
+#endif
+  if (nalloc_verbose) {
+    fprintf(stderr, "failed %s(%zu) \n", op, size);
+#ifdef NALLOC_ASAN
+    __sanitizer_print_stack_trace();
+#endif
+  }
+
+  return false;
+}
+
+//
+static bool nalloc_fail(size_t size, const char *op) {
+  // do not fail before thread init
+  if (nalloc_runs == 0) {
+    return false;
+  }
+  if (__sync_fetch_and_add(&nalloc_running, 1) != 1) {
+    // do not fail allocations outside of fuzzer input
+    // and do not fail inside of this function
+    __sync_fetch_and_sub(&nalloc_running, 1);
+    return false;
+  }
+  nalloc_random_update((uint8_t)size);
+  if (size >= 0x100) {
+    nalloc_random_update((uint8_t)(size >> 8));
+    if (size >= 0x10000) {
+      nalloc_random_update((uint8_t)(size >> 16));
+      // bigger may already fail or oom
+    }
+  }
+  if (((nalloc_random_state ^ nalloc_magic) & nalloc_bitmask) == 0) {
+    void *pc = nalloc_return_address();
+    if (nalloc_backtrace_exclude(size, op, pc)) {
+      __sync_fetch_and_sub(&nalloc_running, 1);
+      return false;
+    }
+    __sync_fetch_and_sub(&nalloc_running, 1);
+    return true;
+  }
+  __sync_fetch_and_sub(&nalloc_running, 1);
+  return false;
+}
+
+// ASAN interceptor for libc routines
+#ifdef NALLOC_ASAN
+extern void *__interceptor_malloc(size_t);
+extern void *__interceptor_calloc(size_t, size_t);
+extern void *__interceptor_realloc(void *, size_t);
+extern void *__interceptor_reallocarray(void *, size_t, size_t);
+
+extern ssize_t __interceptor_read(int, void *, size_t);
+extern ssize_t __interceptor_write(int, const void *, size_t);
+extern ssize_t __interceptor_recv(int, void *, size_t, int);
+extern ssize_t __interceptor_send(int, const void *, size_t, int);
+
+#define nalloc_malloc(s) __interceptor_malloc(s)
+#define nalloc_calloc(s, n) __interceptor_calloc(s, n)
+#define nalloc_realloc(p, s) __interceptor_realloc(p, s)
+#define nalloc_reallocarray(p, s, n) __interceptor_reallocarray(p, s, n)
+
+#define nalloc_read(f, b, s) __interceptor_read(f, b, s)
+#define nalloc_write(f, b, s) __interceptor_write(f, b, s)
+#define nalloc_recv(f, b, s, x) __interceptor_recv(f, b, s, x)
+#define nalloc_send(f, b, s, x) __interceptor_send(f, b, s, x)
+
+#else
+extern void *__libc_malloc(size_t);
+extern void *__libc_calloc(size_t, size_t);
+extern void *__libc_realloc(void *, size_t);
+extern void *__libc_reallocarray(void *, size_t, size_t);
+
+extern ssize_t __read(int, void *, size_t);
+extern ssize_t __write(int, const void *, size_t);
+extern ssize_t __recv(int, void *, size_t, int);
+extern ssize_t __send(int, const void *, size_t, int);
+
+#define nalloc_malloc(s) __libc_malloc(s)
+#define nalloc_calloc(s, n) __libc_calloc(s, n)
+#define nalloc_realloc(p, s) __libc_realloc(p, s)
+#define nalloc_reallocarray(p, s, n) __libc_reallocarray(p, s, n)
+
+#define nalloc_read(f, b, s) __read(f, b, s)
+#define nalloc_write(f, b, s) __write(f, b, s)
+#define nalloc_recv(f, b, s, x) __recv(f, b, s, x)
+#define nalloc_send(f, b, s, x) __send(f, b, s, x)
+#endif
+
+// nalloc standard function overwrites with pseudo-random failures
+ssize_t read(int fd, void *buf, size_t count) {
+  if (nalloc_fail(count, "read")) {
+    errno = EIO;
+    return -1;
+  }
+  return nalloc_read(fd, buf, count);
+}
+
+ssize_t write(int fd, const void *buf, size_t count) {
+  if (nalloc_fail(count, "write")) {
+    errno = EIO;
+    return -1;
+  }
+  return nalloc_write(fd, buf, count);
+}
+
+ssize_t recv(int fd, void *buf, size_t count, int flags) {
+  if (nalloc_fail(count, "recv")) {
+    errno = EIO;
+    return -1;
+  }
+  return nalloc_recv(fd, buf, count, flags);
+}
+
+ssize_t send(int fd, const void *buf, size_t count, int flags) {
+  if (nalloc_fail(count, "send")) {
+    errno = EIO;
+    return -1;
+  }
+  return nalloc_send(fd, buf, count, flags);
+}
+
+void *calloc(size_t nmemb, size_t size) {
+  if (nalloc_fail(size, "calloc")) {
+    errno = ENOMEM;
+    return NULL;
+  }
+  return nalloc_calloc(nmemb, size);
+}
+
+void *malloc(size_t size) {
+  if (nalloc_fail(size, "malloc")) {
+    errno = ENOMEM;
+    return NULL;
+  }
+  return nalloc_malloc(size);
+}
+
+void *realloc(void *ptr, size_t size) {
+  if (nalloc_fail(size, "realloc")) {
+    errno = ENOMEM;
+    return NULL;
+  }
+  return nalloc_realloc(ptr, size);
+}
+
+void *reallocarray(void *ptr, size_t nmemb, size_t size) {
+  if (nalloc_fail(size, "reallocarray")) {
+    errno = ENOMEM;
+    return NULL;
+  }
+  return nalloc_reallocarray(ptr, nmemb, size);
+}
+
+#ifdef __cplusplus
+}  // extern "C" {
+#endif
+
+#endif  // NALLOC_INC_C_