52 lines
1.4 KiB
C
52 lines
1.4 KiB
C
/* CoreOS verity hash */
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#define VERITY_ARG " verity.usrhash="
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#define VERITY_ARG_LENGTH (sizeof (VERITY_ARG) - 1)
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#define VERITY_HASH_LENGTH 64
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#define VERITY_CMDLINE_LENGTH ((VERITY_ARG_LENGTH)+(VERITY_HASH_LENGTH))
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#if defined(__aarch64__)
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# define VERITY_HASH_OFFSET 512
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#elif defined(__i386__) || defined(__amd64__)
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# define VERITY_HASH_OFFSET 0x40
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#else
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# error Unsupported arch
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#endif
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/**
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* grub_pass_verity_hash - Reads the CoreOS verity hash value from a well known
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* kernel image offset and adds a kernel command line argument for it.
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*
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* @pImage: Kernel image buffer.
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* @cmdline: Kernel command line buffer.
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* @cmdline_max_len: Kernel command line buffer length.
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*/
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static inline void grub_pass_verity_hash(const void *pImage,
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char *cmdline,
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grub_size_t cmdline_max_len)
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{
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const char *buf = pImage;
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grub_size_t cmdline_len;
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int i;
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for (i=VERITY_HASH_OFFSET; i<VERITY_HASH_OFFSET + VERITY_HASH_LENGTH; i++)
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{
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if (buf[i] < '0' || buf[i] > '9') // Not a number
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if (buf[i] < 'a' || buf[i] > 'f') // Not a hex letter
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return;
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}
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cmdline_len = grub_strlen(cmdline);
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if (cmdline_len + VERITY_CMDLINE_LENGTH > cmdline_max_len)
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return;
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grub_memcpy (cmdline + cmdline_len, VERITY_ARG, VERITY_ARG_LENGTH);
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cmdline_len += VERITY_ARG_LENGTH;
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grub_memcpy (cmdline + cmdline_len, buf + VERITY_HASH_OFFSET,
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VERITY_HASH_LENGTH);
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cmdline_len += VERITY_HASH_LENGTH;
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cmdline[cmdline_len] = '\0';
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}
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