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From: rcombs <rcombs@rcombs.me>
To: musl@lists.openwall.com
Subject: [musl] [PATCH 2/4] ldso: when run via CLI, set auxv as if the app was loaded by the kernel
Date: Sat, 28 Mar 2020 19:19:26 -0500	[thread overview]
Message-ID: <1585441168-23444-2-git-send-email-rcombs@rcombs.me> (raw)
In-Reply-To: <1585441168-23444-1-git-send-email-rcombs@rcombs.me>

---
 ldso/dynlink.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index c378f00..5f637fd 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -1811,6 +1811,22 @@ void __dls3(size_t *sp, size_t *auxv)
 			}
 			dprintf(1, "\t%s (%p)\n", ldso.name, ldso.base);
 		}
+
+		// Make it look to the app as if it was loaded by the kernel
+		for (i=0; auxv[i]; i+=2) {
+			if (auxv[i] == AT_BASE)
+				auxv[i + 1] = (size_t)ldso.base;
+			if (auxv[i] == AT_PHDR)
+				auxv[i + 1] = (size_t)app.phdr;
+			if (auxv[i] == AT_ENTRY)
+				auxv[i + 1] = aux[AT_ENTRY];
+			if (auxv[i] == AT_PHNUM)
+				auxv[i + 1] = app.phnum;
+			if (auxv[i] == AT_PHENT)
+				auxv[i + 1] = app.phentsize;
+			if (auxv[i] == AT_EXECFN)
+				auxv[i + 1] = (size_t)app.name;
+		}
 	}
 	if (app.tls.size) {
 		libc.tls_head = tls_tail = &app.tls;
-- 
2.7.4

  reply	other threads:[~2020-03-29  0:31 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-29  0:19 [musl] [PATCH 1/4] ldso: add option to rewrite the argv block rcombs
2020-03-29  0:19 ` rcombs [this message]
2020-03-29  0:19 ` [musl] [PATCH 3/4] ldso: move (un)map_library functions to separate file rcombs
2020-03-29  3:07   ` Rich Felker
2020-03-29  0:19 ` [musl] [PATCH 4/4] crt: add dcrt1, with support for locating the dynamic loader at runtime rcombs
2020-03-29  2:54 ` [musl] [PATCH 1/4] ldso: add option to rewrite the argv block Rich Felker

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