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Discarding MD5 array at image load time if its own checksum does not match.

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This commit is contained in:
Thomas Schmitt
2009-08-13 21:41:30 +02:00
parent 40c39af271
commit 74198afa04
4 changed files with 46 additions and 7 deletions
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35
libisofs/fs_image.c
View File

@ -2952,6 +2952,8 @@ int iso_image_import(IsoImage *image, IsoDataSource *src,
uint32_t checksum_size;
size_t size;
uint8_t *rpt;
void *ctx = NULL;
char md5[16];
#endif
if (image == NULL || src == NULL || opts == NULL) {
@ -3166,8 +3168,10 @@ int iso_image_import(IsoImage *image, IsoDataSource *src,
if (ret > 0)
if (checksum_size != 16 || strcmp(checksum_type, "MD5") != 0)
ret = 0;
if (ret > 0) {
size = image->checksum_idx_count / 128 + 1;
if (ret > 0 && image->checksum_idx_count > 1) {
size = image->checksum_idx_count / 128;
if (size * 128 < image->checksum_idx_count)
size++;
image->checksum_array = calloc(size, 2048);
if (image->checksum_array == NULL) {
ret = ISO_OUT_OF_MEM;
@ -3179,7 +3183,29 @@ int iso_image_import(IsoImage *image, IsoDataSource *src,
rpt = (uint8_t *) (image->checksum_array + i * 2048);
ret = src->read_block(src, image->checksum_end_lba + i, rpt);
if (ret <= 0)
goto import_revert;
goto import_cleanup;
}
/* Compute MD5 and compare with recorded MD5 */
ret = iso_md5_start(&ctx);
if (ret < 0) {
ret = ISO_OUT_OF_MEM;
goto import_revert;
}
for (i = 0; i < image->checksum_idx_count - 1; i++)
iso_md5_compute(ctx, image->checksum_array + i * 16, 16);
iso_md5_end(&ctx, md5);
for (i = 0; i < 16; i++)
if (md5[i] != image->checksum_array[
(image->checksum_idx_count - 1) * 16 + i]
)
break;
if (i < 16) {
iso_msg_submit(image->id, ISO_MD5_ARRAY_CORRUPTED, 0,
"MD5 checksum array appears damaged and not trustworthy for verifications.");
free(image->checksum_array);
image->checksum_array = NULL;
image->checksum_idx_count = 0;
}
}
}
@ -3217,9 +3243,10 @@ int iso_image_import(IsoImage *image, IsoDataSource *src,
#ifdef Libisofs_with_checksumS
if (old_checksum_array != NULL)
free(old_checksum_array);
if (ctx != NULL)
iso_md5_end(&ctx, md5);
#endif
return ret;
}

11
libisofs/libisofs.h
View File

@ -5242,11 +5242,20 @@ int iso_md5_end(void **md5_context, char result[16]);
#define ISO_FILE_IMGPATH_WRONG 0xD020FF70
/**
* Offset greater than file size (FAILURE,HIGH, -145)
* Checksum array appears damaged and not trustworthy for verifications.
* (WARNING,HIGH, -145)
* @since 0.6.22
*/
#define ISO_MD5_ARRAY_CORRUPTED 0xD030FF6F
/**
* Offset greater than file size (FAILURE,HIGH, -150)
* @since 0.6.4
*/
#define ISO_FILE_OFFSET_TOO_BIG 0xE830FF6A
/** Charset conversion error (FAILURE,HIGH, -256) */
#define ISO_CHARSET_CONV_ERROR 0xE830FF00

2
libisofs/messages.c
View File

@ -260,6 +260,8 @@ const char *iso_error_to_msg(int errcode)
return "Cannot set global zisofs parameters while filters exist";
case ISO_ZLIB_EARLY_EOF:
return "Premature EOF of zlib input stream";
case ISO_MD5_ARRAY_CORRUPTED:
return "Checksum array appears damaged and not trustworthy for verifications";
default:
return "Unknown error";
}