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Fix possible out of bounds read in PDF parser #1362

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45 changes: 39 additions & 6 deletions libclamav/pdf.c
Original file line number Diff line number Diff line change
Expand Up @@ -1003,8 +1003,26 @@ static size_t find_length(struct pdf_struct *pdf, struct pdf_obj *obj, const cha
return 0;
}

indirect_obj_start = pdf->map + obj->start;
bytes_remaining = pdf->size - obj->start;
if (NULL == obj->objstm) {
indirect_obj_start = (const char *)(obj->start + pdf->map);

if (!CLI_ISCONTAINED(pdf->map, pdf->size, indirect_obj_start, obj->size)) {
cli_dbgmsg("find_length: indirect object found, but not contained in PDF\n");
return 0;
}

bytes_remaining = pdf->size - obj->start;

} else {
indirect_obj_start = (const char *)(obj->start + obj->objstm->streambuf);

if (!CLI_ISCONTAINED(obj->objstm->streambuf, obj->objstm->streambuf_len, indirect_obj_start, obj->size)) {
cli_dbgmsg("find_length: indirect object found, but not contained in PDF streambuf\n");
return 0;
}

bytes_remaining = obj->objstm->streambuf_len - obj->start;
}

/* Ok so we found the indirect object, lets read the value. */
index = pdf_nextobject(indirect_obj_start, bytes_remaining);
Expand Down Expand Up @@ -3260,15 +3278,30 @@ void pdf_handle_enc(struct pdf_struct *pdf)

obj = find_obj(pdf, pdf->objs[0], pdf->enc_objid);
if (!obj) {
cli_dbgmsg("pdf_handle_enc: can't find encrypted object %d %d\n", pdf->enc_objid >> 8, pdf->enc_objid & 0xff);
noisy_warnmsg("pdf_handle_enc: can't find encrypted object %d %d\n", pdf->enc_objid >> 8, pdf->enc_objid & 0xff);
cli_dbgmsg("pdf_handle_enc: can't find encryption object %d %d\n", pdf->enc_objid >> 8, pdf->enc_objid & 0xff);
noisy_warnmsg("pdf_handle_enc: can't find encryption object %d %d\n", pdf->enc_objid >> 8, pdf->enc_objid & 0xff);
return;
}

len = obj->size;

q = (obj->objstm) ? (const char *)(obj->start + obj->objstm->streambuf)
: (const char *)(obj->start + pdf->map);
if (NULL == obj->objstm) {
q = (const char *)(obj->start + pdf->map);

if (!CLI_ISCONTAINED(pdf->map, pdf->size, q, len)) {
cli_dbgmsg("pdf_handle_enc: encryption object found, but not contained in PDF\n");
noisy_warnmsg("pdf_handle_enc: encryption object found, but not contained in PDF\n");
return;
}
} else {
q = (const char *)(obj->start + obj->objstm->streambuf);

if (!CLI_ISCONTAINED(obj->objstm->streambuf, obj->objstm->streambuf_len, q, len)) {
cli_dbgmsg("pdf_handle_enc: encryption object found, but not contained in PDF streambuf\n");
noisy_warnmsg("pdf_handle_enc: encryption object found, but not contained in PDF streambuf\n");
return;
}
}

O = U = UE = StmF = StrF = EFF = NULL;

Expand Down
5 changes: 5 additions & 0 deletions libclamav/pdfng.c
Original file line number Diff line number Diff line change
Expand Up @@ -518,6 +518,11 @@ char *pdf_parse_string(struct pdf_struct *pdf, struct pdf_obj *obj, const char *
if (!(newobj))
return NULL;

if (!CLI_ISCONTAINED(pdf->map, pdf->size, newobj->start, newobj->size)) {
cli_dbgmsg("pdf_parse_string: object not contained in PDF\n");
return NULL;
}

if (newobj == obj)
return NULL;

Expand Down
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