112 lines
3.4 KiB
Diff
112 lines
3.4 KiB
Diff
From: Alan Modra <amodra@gmail.com>
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Date: Tue, 5 Jun 2018 21:04:00 +0930
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Subject: [PATCH] PR23254, ld.bfd mishandles file pointers while scanning
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archive
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Best practice is to not mix lseek/read with fseek/fread on the same
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underlying file descriptor, as not all stdio implementations will cope.
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Since the plugin uses lseek/read while bfd uses fseek/fread this patch
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reopens the file for exclusive use by the plugin rather than trying to
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restore the file descriptor. That allows the plugin to read the file
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after plugin_call_claim_file too.
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bfd/
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PR 23254
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* plugin.c (bfd_plugin_open_input): Allow for possibility of
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nested archives. Open file again for plugin.
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(try_claim): Don't save and restore file position. Close file
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if not claimed.
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* sysdep.h (O_BINARY): Define.
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ld/
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PR 23254
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* plugin.c (plugin_call_claim_file): Revert 2016-07-19 patch.
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(plugin_object_p): Don't dup file descriptor.
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---
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--- a/bfd/plugin.c
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+++ b/bfd/plugin.c
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@@ -165,14 +165,22 @@ bfd_plugin_open_input (bfd *ibfd, struct
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bfd *iobfd;
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iobfd = ibfd;
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- if (ibfd->my_archive && !bfd_is_thin_archive (ibfd->my_archive))
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- iobfd = ibfd->my_archive;
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+ while (iobfd->my_archive
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+ && !bfd_is_thin_archive (iobfd->my_archive))
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+ iobfd = iobfd->my_archive;
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file->name = iobfd->filename;
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if (!iobfd->iostream && !bfd_open_file (iobfd))
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return 0;
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- file->fd = fileno ((FILE *) iobfd->iostream);
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+ /* The plugin API expects that the file descriptor won't be closed
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+ and reused as done by the bfd file cache. So open it again.
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+ dup isn't good enough. plugin IO uses lseek/read while BFD uses
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+ fseek/fread. It isn't wise to mix the unistd and stdio calls on
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+ the same underlying file descriptor. */
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+ file->fd = open (file->name, O_RDONLY | O_BINARY);
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+ if (file->fd < 0)
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+ return 0;
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if (iobfd == ibfd)
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{
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@@ -196,12 +204,12 @@ try_claim (bfd *abfd)
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int claimed = 0;
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struct ld_plugin_input_file file;
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+ file.handle = abfd;
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if (!bfd_plugin_open_input (abfd, &file))
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return 0;
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- file.handle = abfd;
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- off_t cur_offset = lseek (file.fd, 0, SEEK_CUR);
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claim_file (&file, &claimed);
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- lseek (file.fd, cur_offset, SEEK_SET);
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+ if (!claimed)
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+ close (file.fd);
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return claimed;
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}
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--- a/bfd/sysdep.h
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+++ b/bfd/sysdep.h
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@@ -108,6 +108,10 @@ extern char *strrchr ();
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#ifndef O_ACCMODE
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#define O_ACCMODE (O_RDONLY | O_WRONLY | O_RDWR)
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#endif
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+/* Systems that don't already define this, don't need it. */
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+#ifndef O_BINARY
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+#define O_BINARY 0
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+#endif
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#ifndef SEEK_SET
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#define SEEK_SET 0
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--- a/ld/plugin.c
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+++ b/ld/plugin.c
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@@ -1053,14 +1053,10 @@ plugin_call_claim_file (const struct ld_
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{
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if (curplug->claim_file_handler)
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{
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- off_t cur_offset;
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enum ld_plugin_status rv;
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called_plugin = curplug;
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- cur_offset = lseek (file->fd, 0, SEEK_CUR);
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rv = (*curplug->claim_file_handler) (file, claimed);
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- if (!*claimed)
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- lseek (file->fd, cur_offset, SEEK_SET);
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called_plugin = NULL;
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if (rv != LDPS_OK)
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set_plugin_error (curplug->name);
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@@ -1126,12 +1122,6 @@ plugin_object_p (bfd *ibfd)
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}
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file.handle = input;
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- /* The plugin API expects that the file descriptor won't be closed
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- and reused as done by the bfd file cache. So dup one. */
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- file.fd = dup (file.fd);
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- if (file.fd < 0)
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- return NULL;
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-
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input->abfd = abfd;
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input->view_buffer.addr = NULL;
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input->view_buffer.filesize = 0;
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