From ef87d2503498f65577b5d7af07cd453d622fe02c Mon Sep 17 00:00:00 2001
From: Florian Festi <ffesti@redhat.com>
Date: Thu, 18 Jul 2024 13:04:28 +0200
Subject: [PATCH] Reset recursion depth for error message
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Conflict:adapt context
Reference:https://github.com/rpm-software-management/rpm/commit/ef87d2503498f65577b5d7af07cd453d622fe02c

$ rpm --define 'aaa %[%aaa]' --eval '%aaa'

let to a core dump due to a stack overflow. This was cause by the
generation of the error message failing due to being too deep in the
recursion of the macro expansion - creating more error messages.

Resetting the depth counter allows rendering the error message. As we are
failing and breaking off the parse run this is fine to do.

Thanks to Miro Hrončok for reporting

Resolves: #3197
---
 rpmio/macro.c     |  4 +++-
 tests/rpmmacro.at | 22 ++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/rpmio/macro.c b/rpmio/macro.c
index b2fb1326d..3f34f718e 100644
--- a/rpmio/macro.c
+++ b/rpmio/macro.c
@@ -447,9 +447,11 @@ static int mbInit(rpmMacroBuf mb, MacroExpansionData *med, size_t slen)
     if (mb->buf == NULL)
 	mbAllocBuf(mb, slen);
     if (++mb->depth > max_macro_depth) {
+	mb->depth--;
+	/* ensure error message can be rendered */
+	mb->mc->depth = 0;
 	mbErr(mb, 1,
 		_("Too many levels of recursion in macro expansion. It is likely caused by recursive macro declaration.\n"));
-	mb->depth--;
 	return -1;
     }
     med->tpos = mb->tpos; /* save expansion pointer for printExpand */
diff --git a/tests/rpmmacro.at b/tests/rpmmacro.at
index 372cfa3ed..3adf48b61 100644
--- a/tests/rpmmacro.at
+++ b/tests/rpmmacro.at
@@ -133,6 +133,28 @@ runroot rpm --define "this that" --define "that_that foo" --eval '%{expand:%{%{t
 ])
 RPMTEST_CLEANUP
 
+AT_SETUP([recursive macro])
+AT_KEYWORDS([macros])
+RPMTEST_CHECK([
+runroot rpm --define 'aaa %aaa' --eval '%aaa'
+],
+[1],
+[],
+[error: Too many levels of recursion in macro expansion. It is likely caused by recursive macro declaration.
+])
+RPMTEST_CLEANUP
+
+AT_SETUP([recursive expression])
+AT_KEYWORDS([macros])
+RPMTEST_CHECK([
+runroot rpm --define 'aaa %\\[%aaa\\]' --eval '%aaa'
+],
+[1],
+[],
+[error: Too many levels of recursion in macro expansion. It is likely caused by recursive macro declaration.
+])
+RPMTEST_CLEANUP
+
 AT_SETUP([parametrized macro 1])
 AT_KEYWORDS([macros])
 RPMTEST_CHECK([
-- 
2.33.0