From: Mark Wielaard Date: Sun, 19 Dec 2021 22:58:32 +0000 (+0100) Subject: libdwfl: Handle unaligned Ehdr in dwfl_segment_report_module X-Git-Tag: elfutils-0.187~49 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=34ef8b44ed5998b025bd77fde4c71d7d8e585cf0;p=thirdparty%2Felfutils.git libdwfl: Handle unaligned Ehdr in dwfl_segment_report_module The xlate functions only handle correctly aligned buffers. But they do handle src == dest. So if the source buffer isn't aligned correctly just copy it first into the destination (which is already correctly aligned). Signed-off-by: Mark Wielaard --- diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog index 18ffc3476..6c7e0c4a5 100644 --- a/libdwfl/ChangeLog +++ b/libdwfl/ChangeLog @@ -1,3 +1,8 @@ +2021-12-19 Mark Wielaard + + * dwfl_segment_report_module.c (dwfl_segment_report_module): Copy + buffer and set xlatefrom.d_buf to ehdr when buffer is not aligned. + 2021-12-19 Mark Wielaard * dwfl_segment_report_module.c (dwfl_segment_report_module): Check diff --git a/libdwfl/dwfl_segment_report_module.c b/libdwfl/dwfl_segment_report_module.c index a6d6be854..7f7563923 100644 --- a/libdwfl/dwfl_segment_report_module.c +++ b/libdwfl/dwfl_segment_report_module.c @@ -367,6 +367,20 @@ dwfl_segment_report_module (Dwfl *dwfl, int ndx, const char *name, e_ident = ((const unsigned char *) buffer); ei_class = e_ident[EI_CLASS]; ei_data = e_ident[EI_DATA]; + /* buffer may be unaligned, in which case xlatetom would not work. + xlatetom does work when the in and out d_buf are equal (but not + for any other overlap). */ + size_t ehdr_align = (ei_class == ELFCLASS32 + ? __alignof__ (Elf32_Ehdr) + : __alignof__ (Elf64_Ehdr)); + if (((uintptr_t) buffer & (ehdr_align - 1)) != 0) + { + memcpy (&ehdr, buffer, + (ei_class == ELFCLASS32 + ? sizeof (Elf32_Ehdr) + : sizeof (Elf64_Ehdr))); + xlatefrom.d_buf = &ehdr; + } switch (ei_class) { case ELFCLASS32: