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fix bUuDecodeEx: prevent OOM and memory leak on malformed input #148

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fix bUuDecodeEx: prevent OOM and memory leak on malformed input #148

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4a1f36c
fix bUuDecodeEx: prevent OOM and memory leak on malformed input
rdmark Mar 7, 2026
359515b
unit test for: bUuDecodeEx: prevent OOM and memory leak on malformed …
rdmark Mar 7, 2026
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31 changes: 22 additions & 9 deletions bstring/bstraux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -648,10 +648,16 @@ bUuDecLine(void *parm, int ofs, int len)
return ret;
}

struct bsUuCtx {
struct bUuInOut io;
struct bStream * sInp;
};

bstring
bUuDecodeEx(const bstring src, int *badlines)
{
struct bStream *s, *d;
struct bsUuCtx *ctx;
struct tagbstring t;
bstring b;

Expand All @@ -668,11 +674,22 @@ bUuDecodeEx(const bstring src, int *badlines)
if (NULL == b) {
goto error;
}
if (0 > bsread(b, d, INT_MAX)) {
if (src->slen > 0 && 0 > bsread(b, d, src->slen)) {
goto error;
}
exit:
bsclose(d);
/*
* bsUuDecodePart frees ctx->io.dst and ctx->io.src when it signals
* EOF (nulling both pointers), but leaves ctx itself for us to free.
* If the stream was never read (e.g. empty input), all three are still
* live. Either way, bsclose returns the ctx pointer and we own it.
*/
ctx = (struct bsUuCtx *)bsclose(d);
if (ctx) {
bdestroy(ctx->io.dst);
bdestroy(ctx->io.src);
free(ctx);
}
bsclose(s);
return b;
error:
Expand All @@ -681,11 +698,6 @@ bUuDecodeEx(const bstring src, int *badlines)
goto exit;
}

struct bsUuCtx {
struct bUuInOut io;
struct bStream * sInp;
};

static size_t
bsUuDecodePart(void *buff, size_t elsize, size_t nelem, void *parm)
{
Expand Down Expand Up @@ -746,10 +758,11 @@ bsUuDecodePart(void *buff, size_t elsize, size_t nelem, void *parm)
return tsz;
}
}
/* Deallocate once EOF becomes triggered */
/* Release stream buffers on EOF; ctx itself is owned by bUuDecodeEx. */
bdestroy(ctx->io.dst);
ctx->io.dst = NULL;
bdestroy(ctx->io.src);
free(ctx);
ctx->io.src = NULL;
return 0;
}

Expand Down
17 changes: 17 additions & 0 deletions tests/testaux.c
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Original file line number Diff line number Diff line change
Expand Up @@ -510,6 +510,22 @@
}
END_TEST

START_TEST(core_016)

Check warning on line 513 in tests/testaux.c

View check run for this annotation

SonarQubeCloud / SonarCloud Code Analysis

Move declarations of types of parameters for function into list of parameters. 


See more on https://sonarcloud.io/project/issues?id=msteinert_bstring&issues=AZzIkGZRl-vY2hRL8VEO&open=AZzIkGZRl-vY2hRL8VEO&pullRequest=148
{
/* Empty input: bUuDecodeEx must return an empty bstring (not NULL)
* and must not leak the internal decode context. Before the fix,
* bsread was called with INT_MAX on empty input, immediately returned
* BSTR_ERR, and the function took the error path — returning NULL and
* leaking ctx, ctx->io.dst and ctx->io.src. */
struct tagbstring empty = bsStatic("");
int err = 0;
bstring c = bUuDecodeEx(&empty, &err);
ck_assert_ptr_nonnull(c);
ck_assert_int_eq(c->slen, 0);
bdestroy(c);
}
END_TEST

int
main(void)
{
Expand All @@ -532,6 +548,7 @@
tcase_add_test(core, core_012);
tcase_add_test(core, core_013);
tcase_add_test(core, core_014);
tcase_add_test(core, core_016);
suite_add_tcase(suite, core);
/* Run tests */
SRunner *runner = srunner_create(suite);
Expand Down