From 0a7e1e44143be5bd468a07d4b71a28a1d45c3ce4 Mon Sep 17 00:00:00 2001
From: Pompolic <pompolic@special-circumstanc.es>
Date: Thu, 22 Jul 2021 23:14:22 +0200
Subject: [PATCH] Partial ASCII85 digit group fixes
- off by one in act_partial3group led to uninitialized memory ending up in parse result
- Check the numerical value of the resulting HBytes against A85GRPMAX in validations
- Mark printfs as debug output
---
pdf.c | 33 ++++++++++++++++++---------------
1 file changed, 18 insertions(+), 15 deletions(-)
diff --git a/pdf.c b/pdf.c
index b9b0c05..0bd4483 100644
--- a/pdf.c
+++ b/pdf.c
@@ -427,7 +427,7 @@ act_a85group(const HParseResult *p, void *u)
bytes[1] = (fourbytes & 0x00FF0000) >> 16;
bytes[2] = (fourbytes & 0x0000FF00) >> 8;
bytes[3] = (fourbytes & 0x000000FF);
- fprintf(stdout, "%6x ==> %2x %2x %2x %2x\n", fourbytes, bytes[0], bytes[1], bytes[2], bytes[3]);
+ fprintf(stdout, "%6x ==> %2x %2x %2x %2x\n", fourbytes, bytes[0], bytes[1], bytes[2], bytes[3]); // XXX debug
}
return H_MAKE_BYTES(bytes, 4);
}
@@ -451,10 +451,9 @@ act_a85partial2group(const HParseResult *p, void *u)
fourbytes, fourbytes); // XXX DEBUG
}
- // fill the other bytes with u (dec 117-33)
- // XXX I'm confused. I think to restore the padding, '!' needs to be added instead of 'u'
+ // fill the other bytes with 0
for (int i=2; i<5; i++) {
- fourbytes = fourbytes * 85 + 84;
+ fourbytes = fourbytes * 85;
}
// truncate and return only the high order byte
@@ -467,7 +466,7 @@ act_a85partial2group(const HParseResult *p, void *u)
bool
validate_a85partial2group(HParseResult *p, void *u)
{
- return H_CAST_BYTES(p->ast).token[0] <= A85GRPMAX;
+ return ((H_CAST_BYTES(p->ast).token[0] << 24) + (H_CAST_BYTES(p->ast).token[1] << 16)) <= A85GRPMAX;
}
HParsedToken *
@@ -487,27 +486,27 @@ act_a85partial3group(const HParseResult *p, void *u)
fourbytes = fourbytes * 85 + H_CAST_UINT(digits[i]->seq->elements[0]);
}
- // fill the other bytes with u (dec 117-33)
- for (int i=4; i<5; i++) {
- fourbytes = fourbytes * 85 + 84;
+ // fill the other bytes with 0
+ for (int i=3; i<5; i++) {
+ fourbytes = fourbytes * 85;
}
// truncate and return only the high order bytes
// I think groups of 3 A85 characters decode to 2 bytes
bytes[0] = (fourbytes & 0xFF000000) >> 24;
bytes[1] = (fourbytes & 0x00FF0000) >> 16;
- bytes[2] = (fourbytes & 0x0000FF00) >> 8;
+ //bytes[2] = (fourbytes & 0x0000FF00) >> 8;
- fprintf(stdout, "act_a85partial3group: %4x (%d) ==> %2x %2x %2x \n", fourbytes, fourbytes, bytes[0],
- bytes[1], bytes[2]); // XXX DEBUG
+ fprintf(stdout, "act_a85partial3group: %4x (%d) ==> %2x %2x\n", fourbytes, fourbytes, bytes[0],
+ bytes[1]); // XXX DEBUG
- return H_MAKE_BYTES(bytes, 3); // XXX test: should this be 2?
+ return H_MAKE_BYTES(bytes, 2);
}
bool
validate_a85partial3group(HParseResult *p, void *u)
{
- return H_CAST_UINT(p->ast) <= A85GRPMAX;
+ return ((H_CAST_BYTES(p->ast).token[0] << 24) + (H_CAST_BYTES(p->ast).token[1] << 16) + (H_CAST_BYTES(p->ast).token[2] << 8)) <= A85GRPMAX;
}
HParsedToken *
@@ -526,6 +525,10 @@ act_a85partial4group(const HParseResult *p, void *u)
assert(digits[i]->token_type == TT_SEQUENCE);
fourbytes = fourbytes * 85 + H_CAST_UINT(digits[i]->seq->elements[0]);
}
+
+ for (int i=4; i<5; i++) {
+ fourbytes = fourbytes * 85;
+ }
// truncate and return only the high order bytes
bytes[0] = (fourbytes & 0xFF000000) >> 24;
bytes[1] = (fourbytes & 0x00FF0000) >> 16;
@@ -539,7 +542,7 @@ act_a85partial4group(const HParseResult *p, void *u)
bool
validate_a85partial4group(HParseResult *p, void *u)
{
- return H_CAST_UINT(p->ast) <= A85GRPMAX;
+ return ((H_CAST_BYTES(p->ast).token[0] << 24) + (H_CAST_BYTES(p->ast).token[1] << 16) + (H_CAST_BYTES(p->ast).token[2] << 8)) <= A85GRPMAX;
}
HParsedToken *
@@ -602,7 +605,7 @@ act_a85string(const HParseResult *p, void *u)
chunks->elements[i]->bytes.len == 4);
memcpy(result_bytes + out_pos, chunks->elements[i]->bytes.token, 4);
fprintf(stdout, "%2x%2x%2x%2x - %8x\n", result_bytes[out_pos], result_bytes[out_pos+1],
- result_bytes[out_pos+2], result_bytes[out_pos+3], *((unsigned int *)(chunks->elements[i]->bytes.token)));
+ result_bytes[out_pos+2], result_bytes[out_pos+3], *((unsigned int *)(chunks->elements[i]->bytes.token))); // XXX DEBUG
out_pos += 4;
}
if (last_chunk.len) {
--
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