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    Subject[PATCH v2 1/8] x86/kaslr: Make command line handling safer
    Date
    Handle the possibility that the command line is NULL.

    Replace open-coded strlen with a function call.

    Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
    ---
    arch/x86/boot/compressed/kaslr.c | 17 +++++++++--------
    1 file changed, 9 insertions(+), 8 deletions(-)

    diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c
    index d7408af55738..a4af89646094 100644
    --- a/arch/x86/boot/compressed/kaslr.c
    +++ b/arch/x86/boot/compressed/kaslr.c
    @@ -268,15 +268,19 @@ static void parse_gb_huge_pages(char *param, char *val)
    static void handle_mem_options(void)
    {
    char *args = (char *)get_cmd_line_ptr();
    - size_t len = strlen((char *)args);
    + size_t len;
    char *tmp_cmdline;
    char *param, *val;
    u64 mem_size;

    + if (!args)
    + return;
    +
    if (!strstr(args, "memmap=") && !strstr(args, "mem=") &&
    !strstr(args, "hugepages"))
    return;

    + len = strlen(args);
    tmp_cmdline = malloc(len + 1);
    if (!tmp_cmdline)
    error("Failed to allocate space for tmp_cmdline");
    @@ -399,8 +403,7 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
    {
    unsigned long init_size = boot_params->hdr.init_size;
    u64 initrd_start, initrd_size;
    - u64 cmd_line, cmd_line_size;
    - char *ptr;
    + unsigned long cmd_line, cmd_line_size = 0;

    /*
    * Avoid the region that is unsafe to overlap during
    @@ -421,12 +424,10 @@ static void mem_avoid_init(unsigned long input, unsigned long input_size,
    /* No need to set mapping for initrd, it will be handled in VO. */

    /* Avoid kernel command line. */
    - cmd_line = (u64)boot_params->ext_cmd_line_ptr << 32;
    - cmd_line |= boot_params->hdr.cmd_line_ptr;
    + cmd_line = get_cmd_line_ptr();
    /* Calculate size of cmd_line. */
    - ptr = (char *)(unsigned long)cmd_line;
    - for (cmd_line_size = 0; ptr[cmd_line_size++];)
    - ;
    + if (cmd_line)
    + cmd_line_size = strlen((char *)cmd_line);
    mem_avoid[MEM_AVOID_CMDLINE].start = cmd_line;
    mem_avoid[MEM_AVOID_CMDLINE].size = cmd_line_size;
    add_identity_map(mem_avoid[MEM_AVOID_CMDLINE].start,
    --
    2.26.2
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