再一次关于嵌入式：在Embox项目中寻找错误

分析

pvs-studio-analyzer analyze -- make

pvs-studio-analyzer analyze -o /path/to/output.log

plog-converter -t tasklist -o /path/to/output.tasks /path/to/project

怪周期

int main(int argc, char **argv) {
  ....

  while (dp.skip != 0 ) {
    n_read = read(ifd, tbuf, dp.bs);
    if (n_read < 0) {
      err = -errno;
      goto out_cmd;
    }
    if (n_read == 0) {
      goto out_cmd;
    }

    dp.skip --;
  } while (dp.skip != 0);       // <=

  do {
    n_read = read(ifd, tbuf, dp.bs);
    if (n_read < 0) {
      err = -errno;
      break;
    }

    if (n_read == 0) {
      break;
    }

    ....

    dp.count --;
  } while (dp.count != 0);
  ....
}

内存泄漏

int krename(const char *oldpath, const char *newpath) {
  
  char *newpatharg, *oldpatharg;

  ....

  oldpatharg =
    calloc(strlen(oldpath) + diritemlen + 2, sizeof(char));
  newpatharg =
    calloc(strlen(newpath) + diritemlen + 2, sizeof(char));
  if (NULL == oldpatharg || NULL == newpatharg) {
    SET_ERRNO(ENOMEM);
    return -1;
  }

  ....
}

• V773 The function was exited without releasing the 'newpatharg' pointer. A memory leak is possible. kfsop.c 611
• V773 The function was exited without releasing the 'oldpatharg' pointer. A memory leak is possible. kfsop.c 611

static int block_dev_test(....) {
  int8_t *read_buf, *write_buf;
  
  ....

  read_buf = malloc(blk_sz * m_blocks);
  write_buf = malloc(blk_sz * m_blocks);

  if (read_buf == NULL || write_buf == NULL) {
    printf("Failed to allocate memory for buffer!\n");

    if (read_buf != NULL) {
      free(read_buf);
    }

    if (write_buf != NULL) {
      free(write_buf);
    }

    return -ENOMEM;
  }

  if (s_block >= blocks) {
    printf("Starting block should be less than number of blocks\n");
    return -EINVAL;            // <=
  }

  ....
}

• V773 The function was exited without releasing the 'read_buf' pointer. A memory leak is possible. block_dev_test.c 195
• V773 The function was exited without releasing the 'write_buf' pointer. A memory leak is possible. block_dev_test.c 195

指针处理不当

static int scsi_write(struct block_dev *bdev, char *buffer,
                      size_t count, blkno_t blkno) {
  struct scsi_dev *sdev;
  int blksize;

  ....

  sdev = bdev->privdata;
  blksize = sdev->blk_size; // <=

  if (!sdev) {              // <=
    return -ENODEV;
  }

  ....
}

void xdrrec_create(....)
{
  char *buff;

  ....

  buff = (char *)malloc(sendsz + recvsz);
  assert(buff != NULL);

  ....

  xs->extra.rec.in_base = xs->extra.rec.in_curr = buff;
  xs->extra.rec.in_boundry 
    = xs->extra.rec.in_base + recvsz;                    // <=

  ....
  xs->extra.rec.out_base
    = xs->extra.rec.out_hdr = buff + recvsz;             // <= 
  xs->extra.rec.out_curr 
    = xs->extra.rec.out_hdr + sizeof(union xdrrec_hdr);

  ....
}

• V769'xs- > extra.rec.in_base + recvsz'表达式中的'xs-> extra.rec.in_base'指针可以为nullptr。在这种情况下，结果值将毫无意义，因此不应使用。检查行：56，48。xdr_rec.c 56
• V769'buff + recvsz'表达式中的'buff'指针可以为nullptr。在这种情况下，结果值将毫无意义，因此不应使用。检查行：61，​​48。xdr_rec.c 61

数组处理不正确

int fat_read_filename(struct fat_file_info *fi,
                      void *p_scratch,
                      char *name) {
  int offt = 1;

  ....

  offt = strlen(name);
  while (name[offt - 1] == ' ' && offt > 0) { // <=
    name[--offt] = '\0';
  }
  log_debug("name(%s)", name);

  return DFS_OK;
}

可疑情况

int index_descriptor_cloexec_set(int fd, int cloexec) {
  struct idesc_table *it;

  it = task_resource_idesc_table(task_self());
  assert(it);

  if (cloexec | FD_CLOEXEC) {
    idesc_cloexec_set(it->idesc_table[fd]);
  } else {
    idesc_cloexec_clear(it->idesc_table[fd]);
  }
  return 0;
}

#define FD_CLOEXEC 0x0010

整数除法

#define SBSIZE    1024

static int ext2fs_format(struct block_dev *bdev, void *priv) {
  size_t dev_bsize;
  float dev_factor;

  ....

  dev_size = block_dev_size(bdev);
  dev_bsize = block_dev_block_size(bdev);
  dev_factor = SBSIZE / dev_bsize;            // <=

  ext2_dflt_sb(&sb, dev_size, dev_factor);
  ext2_dflt_gd(&sb, &gd);

  ....
}

static void ext2_dflt_sb(struct ext2sb *sb, size_t dev_size, float dev_factor);

dev_factor = float(SBSIZE) / dev_bsize;

未验证的输入

int main(int argc, char **argv) {
  int ret;
  char text[SMTP_TEXT_LEN + 1];

  ....

  if (NULL == fgets(&text[0], sizeof text - 2, /* for \r\n */
      stdin)) { ret = -EIO; goto error; }
    text[strlen(&text[0]) - 1] = '\0'; /* remove \n */    // <=

  ....
}

text[ 0 - 1 ] = '\0';

• V1010未检查的污染数据用于索引：“ strlen（＆from [0]）”。sendmail.c 55
• V1010未检查的污染数据用于索引：“ strlen（＆到[0]）”。sendmail.c 65

米斯拉

/* find and read symlink file */
static int ext2_read_symlink(struct nas *nas,
                             uint32_t parent_inumber,
                             const char **cp) {
  char namebuf[MAXPATHLEN + 1];

  ....

  *cp = namebuf;              // <=
  if (*namebuf != '/') {
    inumber = parent_inumber;
  } else {
    inumber = (uint32_t) EXT2_ROOTINO;
  }
  rc = ext2_read_inode(nas, inumber);

  return rc;
} 

• V2548 [MISRA C 18.6]本地变量'dst_haddr'的地址不应存储在该变量范围之外。net_tx.c 82

结论